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USB 2.0 Dropped frames

Posted: Tue Apr 30, 2019 3:54 pm
by John Westlake
I have designed a range of audio streamers based on the CM3 - with more designs in the pipework.

The streamers interface to the external Audio DAC via USB 2.0, however under certain conditions we experience random audible popping and clicks which are very hard to diagnose.

It would seem that some USB "interfaces" in the DAC's are more or less sensitive to the issue - with XMOS based devices working better then others (but still can be sensitive).

What is the root cause of the CM3 USB interface weakness? - my uneducated understanding is that the USB host controller in the Broadcom IC does not support DMA and that interrupts must be serviced by the CPUs (within a a certain time window (1ms?) otherwise the frame is dropped). Can anyone clarify the real issue and can anything be done to improve the USB stability so we don't drop frames.

I'm no software guy, but could not one ARM CPU core be dedicated JUST to servicing the USB interrupts? this might be seen as rather wasteful, but Audio throughput without dropouts is critical in our application - over any other potential performance hit.

When I look at the CPU loading the system is operating at around 7% to 10% loading (and this would appear to be just a single core) - yet we still experience heavy dropouts especially when transparency mode is enabled on Chromium web browser (highlighting an object in the browser session).

Looking at the CPU loading and there seems little correlation with CPU load (never anywhere near 100%) and real world dropouts...

I understand that in the very early days USB caused a whole bag of hurt - with even keystrokes being missed .... Its hard to really understand the whole issue - could RPi please comment and advise what can be done.

Can the Broadcom USB host controller be made to support USB2.0 data without dropping frames? - we are operating no where near the Max 480Mbps USB 2.0 data limit so hope it can be resolved at a the Kernal level.. somehow... :)

I expect that Broadcom and Rpi are working on the next Gen SoC, can a real USB host controller (I suspect USB3.0 is being considered) be included - maybe a couple of USB hosts :)

Re: USB 2.0 Dropped frames

Posted: Thu May 16, 2019 6:38 pm
by mastercheif
Has anybody found a solution to this?

Re: USB 2.0 Dropped frames

Posted: Fri May 17, 2019 9:18 am
by jdb
Please post
- the full output of dmesg after playback has started and you've had at least one corrupt audio frame
- the output of lsusb -v and lsusb -t

Re: USB 2.0 Dropped frames

Posted: Thu May 23, 2019 1:02 am
by John Westlake
OK, noted, will do.

Re: USB 2.0 Dropped frames

Posted: Tue Jun 04, 2019 5:18 pm
by mikelangeloz
Hi. It is to be noted that we do get small dropouts (about 3ms) without any trace in dmesg or journal. We do get them when playing DSD256 in DoP mode.

Those are the logs you requested:

DMESG

Code: Select all

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.9.65-v7+ (volumio@udoo-x86) (gcc version 4.8.3 20140106 (prerelease) (crosstool-NG linaro-1.13.1-4.8-2014.01 - Linaro GCC 2013.11) ) #1 SMP Thu Jul 19 18:43:14 UTC 2018
[    0.000000] CPU: ARMv7 Processor [410fd034] revision 4 (ARMv7), cr=10c5383d
[    0.000000] CPU: div instructions available: patching division code
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] OF: fdt:Machine model: Raspberry Pi Compute Module 3 Rev 1.0
[    0.000000] cma: Reserved 8 MiB at 0x3b800000
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] On node 0 totalpages: 245760
[    0.000000] free_area_init_node: node 0, pgdat 80c6f380, node_mem_map baf86000
[    0.000000]   Normal zone: 2160 pages used for memmap
[    0.000000]   Normal zone: 0 pages reserved
[    0.000000]   Normal zone: 245760 pages, LIFO batch:31
[    0.000000] percpu: Embedded 14 pages/cpu @baf41000 s25600 r8192 d23552 u57344
[    0.000000] pcpu-alloc: s25600 r8192 d23552 u57344 alloc=14*4096
[    0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 243600
[    0.000000] Kernel command line: bcm2708_fb.fbwidth=640 bcm2708_fb.fbheight=480 bcm2708_fb.fbswap=1 smsc95xx.macaddr=B8:27:EB:1F:E8:6F vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000  splash quiet plymouth.ignore-serial-consoles dwc_otg.fiq_enable=1 dwc_otg.fiq_fsm_enable=1 dwc_otg.fiq_fsm_mask=0xF dwc_otg.nak_holdoff=1 imgpart=/dev/mmcblk0p2 imgfile=/volumio_current.sqsh elevator=noop rootwait smsc95xx.turbo_mode=N bootdelay=5 logo.nologo vt.global_cursor_default=0 loglevel=0 consoleblank=0
[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] Memory: 942104K/983040K available (7168K kernel code, 486K rwdata, 2012K rodata, 1024K init, 770K bss, 32744K reserved, 8192K cma-reserved)
[    0.000000] Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
    vmalloc : 0xbc800000 - 0xff800000   (1072 MB)
    lowmem  : 0x80000000 - 0xbc000000   ( 960 MB)
    modules : 0x7f000000 - 0x80000000   (  16 MB)
      .text : 0x80008000 - 0x80800000   (8160 kB)
      .init : 0x80b00000 - 0x80c00000   (1024 kB)
      .data : 0x80c00000 - 0x80c7981c   ( 487 kB)
       .bss : 0x80c7b000 - 0x80d3b964   ( 771 kB)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] Hierarchical RCU implementation.
[    0.000000]  Build-time adjustment of leaf fanout to 32.
[    0.000000] NR_IRQS:16 nr_irqs:16 16
[    0.000000] arm_arch_timer: Architected cp15 timer(s) running at 19.20MHz (phys).
[    0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x46d987e47, max_idle_ns: 440795202767 ns
[    0.000006] sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 4398046511078ns
[    0.000018] Switching to timer-based delay loop, resolution 52ns
[    0.000273] Console: colour dummy device 80x30
[    0.000291] console [tty0] enabled
[    0.000311] Calibrating delay loop (skipped), value calculated using timer frequency.. 38.40 BogoMIPS (lpj=192000)
[    0.000326] pid_max: default: 32768 minimum: 301
[    0.000605] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.000615] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.001683] Disabling memory control group subsystem
[    0.001752] CPU: Testing write buffer coherency: ok
[    0.001786] ftrace: allocating 22388 entries in 66 pages
[    0.048943] CPU0: update cpu_capacity 1024
[    0.048956] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[    0.048993] Setting up static identity map for 0x100000 - 0x100034
[    0.050893] CPU1: update cpu_capacity 1024
[    0.050900] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[    0.051555] CPU2: update cpu_capacity 1024
[    0.051561] CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
[    0.052201] CPU3: update cpu_capacity 1024
[    0.052207] CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
[    0.052297] Brought up 4 CPUs
[    0.052307] SMP: Total of 4 processors activated (153.60 BogoMIPS).
[    0.052311] CPU: All CPU(s) started in HYP mode.
[    0.052314] CPU: Virtualization extensions available.
[    0.053048] devtmpfs: initialized
[    0.064292] VFP support v0.3: implementor 41 architecture 3 part 40 variant 3 rev 4
[    0.064558] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.064574] futex hash table entries: 1024 (order: 4, 65536 bytes)
[    0.065122] pinctrl core: initialized pinctrl subsystem
[    0.066034] NET: Registered protocol family 16
[    0.068417] DMA: preallocated 1024 KiB pool for atomic coherent allocations
[    0.077411] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
[    0.077417] hw-breakpoint: maximum watchpoint size is 8 bytes.
[    0.077561] Serial: AMBA PL011 UART driver
[    0.079447] bcm2835-mbox 3f00b880.mailbox: mailbox enabled
[    0.149799] bcm2835-dma 3f007000.dma: DMA legacy API manager at bc80f000, dmachans=0x1
[    0.151661] SCSI subsystem initialized
[    0.151818] usbcore: registered new interface driver usbfs
[    0.151893] usbcore: registered new interface driver hub
[    0.151983] usbcore: registered new device driver usb
[    0.158746] raspberrypi-firmware soc:firmware: Attached to firmware from 2018-07-17 13:23
[    0.160311] clocksource: Switched to clocksource arch_sys_counter
[    0.204609] VFS: Disk quotas dquot_6.6.0
[    0.204683] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[    0.204880] FS-Cache: Loaded
[    0.205132] CacheFiles: Loaded
[    0.217390] NET: Registered protocol family 2
[    0.218259] TCP established hash table entries: 8192 (order: 3, 32768 bytes)
[    0.218367] TCP bind hash table entries: 8192 (order: 4, 65536 bytes)
[    0.218552] TCP: Hash tables configured (established 8192 bind 8192)
[    0.218644] UDP hash table entries: 512 (order: 2, 16384 bytes)
[    0.218686] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
[    0.218897] NET: Registered protocol family 1
[    0.219314] RPC: Registered named UNIX socket transport module.
[    0.219319] RPC: Registered udp transport module.
[    0.219323] RPC: Registered tcp transport module.
[    0.219327] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    0.219565] Trying to unpack rootfs image as initramfs...
[    1.092344] Freeing initrd memory: 10444K
[    1.098387] hw perfevents: enabled with armv7_cortex_a7 PMU driver, 7 counters available
[    1.100762] workingset: timestamp_bits=14 max_order=18 bucket_order=4
[    1.116999] FS-Cache: Netfs 'nfs' registered for caching
[    1.117977] NFS: Registering the id_resolver key type
[    1.118001] Key type id_resolver registered
[    1.118006] Key type id_legacy registered
[    1.120437] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
[    1.120550] io scheduler noop registered (default)
[    1.120555] io scheduler deadline registered
[    1.120857] io scheduler cfq registered
[    1.126570] BCM2708FB: allocated DMA memory fb910000
[    1.126592] BCM2708FB: allocated DMA channel 0 @ bc80f000
[    1.136225] Console: switching to colour frame buffer device 80x30
[    1.143321] bcm2835-rng 3f104000.rng: hwrng registered
[    1.143428] vc-mem: phys_addr:0x00000000 mem_base=0x3ec00000 mem_size:0x40000000(1024 MiB)
[    1.143936] vc-sm: Videocore shared memory driver
[    1.158764] brd: module loaded
[    1.167634] loop: module loaded
[    1.167645] Loading iSCSI transport class v2.0-870.
[    1.168161] usbcore: registered new interface driver smsc95xx
[    1.168176] dwc_otg: version 3.00a 10-AUG-2012 (platform bus)
[    1.396217] Core Release: 2.80a
[    1.396226] Setting default values for core params
[    1.396256] Finished setting default values for core params
[    1.596648] Using Buffer DMA mode
[    1.596653] Periodic Transfer Interrupt Enhancement - disabled
[    1.596657] Multiprocessor Interrupt Enhancement - disabled
[    1.596664] OTG VER PARAM: 0, OTG VER FLAG: 0
[    1.596674] Dedicated Tx FIFOs mode
[    1.597012] WARN::dwc_otg_hcd_init:1032: FIQ DMA bounce buffers: virt = 0xbb904000 dma = 0xfb904000 len=9024
[    1.597035] FIQ FSM acceleration enabled for :
Non-periodic Split Transactions
Periodic Split Transactions
High-Speed Isochronous Endpoints
Interrupt/Control Split Transaction hack enabled
[    1.597041] dwc_otg: Microframe scheduler enabled
[    1.597089] WARN::hcd_init_fiq:459: FIQ on core 1 at 0x8057e2c8
[    1.597099] WARN::hcd_init_fiq:460: FIQ ASM at 0x8057e624 length 36
[    1.597109] WARN::hcd_init_fiq:486: MPHI regs_base at 0xbc87a000
[    1.597169] dwc_otg 3f980000.usb: DWC OTG Controller
[    1.597202] dwc_otg 3f980000.usb: new USB bus registered, assigned bus number 1
[    1.597233] dwc_otg 3f980000.usb: irq 62, io mem 0x00000000
[    1.597279] Init: Port Power? op_state=1
[    1.597283] Init: Power Port (0)
[    1.597488] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[    1.597498] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    1.597506] usb usb1: Product: DWC OTG Controller
[    1.597514] usb usb1: Manufacturer: Linux 4.9.65-v7+ dwc_otg_hcd
[    1.597522] usb usb1: SerialNumber: 3f980000.usb
[    1.598330] hub 1-0:1.0: USB hub found
[    1.598368] hub 1-0:1.0: 1 port detected
[    1.599038] dwc_otg: FIQ enabled
[    1.599042] dwc_otg: NAK holdoff enabled
[    1.599046] dwc_otg: FIQ split-transaction FSM enabled
[    1.599060] Module dwc_common_port init
[    1.599292] usbcore: registered new interface driver usb-storage
[    1.599530] mousedev: PS/2 mouse device common for all mice
[    1.600586] bcm2835-wdt 3f100000.watchdog: Broadcom BCM2835 watchdog timer
[    1.600876] bcm2835-cpufreq: min=600000 max=1200000
[    1.601289] sdhci: Secure Digital Host Controller Interface driver
[    1.601293] sdhci: Copyright(c) Pierre Ossman
[    1.603451] sdhost-bcm2835 3f202000.sdhost: could not get clk, deferring probe
[    1.603654] sdhci-pltfm: SDHCI platform and OF driver helper
[    1.604073] ledtrig-cpu: registered to indicate activity on CPUs
[    1.604167] hidraw: raw HID events driver (C) Jiri Kosina
[    1.604338] usbcore: registered new interface driver usbhid
[    1.604343] usbhid: USB HID core driver
[    1.605081] vchiq: vchiq_init_state: slot_zero = 0xbb980000, is_master = 0
[    1.606428] [vc_sm_connected_init]: start
[    1.615069] [vc_sm_connected_init]: end - returning 0
[    1.615439] Initializing XFRM netlink socket
[    1.615462] NET: Registered protocol family 17
[    1.615561] Key type dns_resolver registered
[    1.616133] Registering SWP/SWPB emulation handler
[    1.616816] registered taskstats version 1
[    1.622196] uart-pl011 3f201000.serial: cts_event_workaround enabled
[    1.622261] 3f201000.serial: ttyAMA0 at MMIO 0x3f201000 (irq = 87, base_baud = 0) is a PL011 rev2
[    1.625721] sdhost: log_buf @ bb907000 (fb907000)
[    1.700345] mmc0: sdhost-bcm2835 loaded - DMA enabled (>1)
[    1.700455] of_cfs_init
[    1.700637] of_cfs_init: OK
[    1.721906] Freeing unused kernel memory: 1024K
[    1.810459] Indeed it is in host mode hprt0 = 00021501
[    1.860078] initramfs: Booting Volumio for BCM2835
[    1.860244] initramfs: This script mounts rootfs RO with an overlay RW layer.
[    1.875410] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[    1.881050] initramfs: IMGPART=/dev/mmcblk0p2
[    1.881188] initramfs: IMGFILE=/volumio_current.sqsh
[    1.881390] initramfs: Boot delay (except first time) will be 5 seconds
[    1.881705] initramfs: /dev/mmcblk0p2 not detected,retrying mdev in 5 seconds
[    1.898253] random: fast init done
[    1.901658] mmc0: new high speed MMC card at address 0001
[    1.902363] mmcblk0: mmc0:0001 MAG2GC 14.6 GiB
[    1.902615] mmcblk0boot0: mmc0:0001 MAG2GC partition 1 4.00 MiB
[    1.902863] mmcblk0boot1: mmc0:0001 MAG2GC partition 2 4.00 MiB
[    1.903100] mmcblk0rpmb: mmc0:0001 MAG2GC partition 3 4.00 MiB
[    1.906485]  mmcblk0: p1 p2 p3
[    2.010352] usb 1-1: new high-speed USB device number 2 using dwc_otg
[    2.010479] Indeed it is in host mode hprt0 = 00001101
[    2.240594] usb 1-1: New USB device found, idVendor=0424, idProduct=9514
[    2.240605] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    2.241332] hub 1-1:1.0: USB hub found
[    2.241422] hub 1-1:1.0: 5 ports detected
[    2.526596] initramfs: /dev/mmcblk0p2:
[    2.547020] EXT4-fs (mmcblk0p2): recovery complete
[    2.548226] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[    2.550703] initramfs: Doing a 5 second delay here to give kernel load a headstart
[    2.560384] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
[    2.690605] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00
[    2.690616] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    2.693459] smsc95xx v1.0.5
[    2.783965] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:1f:e8:6f
[    2.880345] usb 1-1.4: new high-speed USB device number 4 using dwc_otg
[    3.010579] usb 1-1.4: New USB device found, idVendor=0424, idProduct=2412
[    3.010590] usb 1-1.4: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    3.011236] hub 1-1.4:1.0: USB hub found
[    3.011328] hub 1-1.4:1.0: 2 ports detected
[    3.110341] usb 1-1.5: new high-speed USB device number 5 using dwc_otg
[    3.241108] usb 1-1.5: New USB device found, idVendor=0bda, idProduct=b720
[    3.241118] usb 1-1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[    3.241126] usb 1-1.5: Product: 802.11n WLAN Adapter
[    3.241133] usb 1-1.5: Manufacturer: Realtek
[    3.241141] usb 1-1.5: SerialNumber: 00e04c000001
[    3.340339] usb 1-1.4.2: new high-speed USB device number 6 using dwc_otg
[    3.471016] usb 1-1.4.2: New USB device found, idVendor=2772, idProduct=0230
[    3.471027] usb 1-1.4.2: New USB device strings: Mfr=1, Product=3, SerialNumber=0
[    3.471034] usb 1-1.4.2: Product: Pre Box S2 Digital
[    3.471042] usb 1-1.4.2: Manufacturer: Pro-Ject
[    3.474563] input: Pro-Ject Pre Box S2 Digital as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/1-1.4.2/1-1.4.2:1.3/0003:2772:0230.0001/input/input0
[    3.540579] hid-generic 0003:2772:0230.0001: input,hidraw0: USB HID v1.10 Device [Pro-Ject Pre Box S2 Digital] on usb-3f980000.usb-1.4.2/input3
[    7.554549] initramfs: Checking for USB updates
[    7.653665] initramfs: No USB device detected (when incorrect, try adding 'bootdelay=5' to your boot cmdline)
[    7.832584] FAT-fs (mmcblk0p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
[    7.921750] FAT-fs (mmcblk0p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
[    9.366926] EXT4-fs (mmcblk0p3): 3 orphan inodes deleted
[    9.366935] EXT4-fs (mmcblk0p3): recovery complete
[    9.385714] EXT4-fs (mmcblk0p3): mounted filesystem with ordered data mode. Opts: (null)
[    9.388730] initramfs: With Option:
[    9.514053] initramfs: VOLUMIO_VERSION="1.018"
[    9.514210] initramfs: Finish initramfs, continue booting Volumio
[    9.879961] systemd[1]: systemd 215 running in system mode. (+PAM +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ -SECCOMP -APPARMOR)
[    9.880286] systemd[1]: Detected architecture 'arm'.
[   10.007057] NET: Registered protocol family 10
[   10.008624] systemd[1]: Inserted module 'ipv6'
[   10.011224] systemd[1]: Set hostname to <stack-audio-link>.
[   10.273236] systemd[1]: [/lib/systemd/system/mpd.service:19] Unknown lvalue 'ProtectKernelTunables' in section 'Service'
[   10.273300] systemd[1]: [/lib/systemd/system/mpd.service:20] Unknown lvalue 'ProtectControlGroups' in section 'Service'
[   10.273358] systemd[1]: [/lib/systemd/system/mpd.service:21] Unknown lvalue 'ProtectKernelModules' in section 'Service'
[   10.273430] systemd[1]: [/lib/systemd/system/mpd.service:24] Unknown lvalue 'RestrictNamespaces' in section 'Service'
[   10.305834] systemd[1]: [/lib/systemd/system/volumio-kiosk.service:11] CPU scheduling priority is out of range, ignoring: 1
[   10.327611] systemd[1]: Cannot add dependency job for unit display-manager.service, ignoring: Unit display-manager.service failed to load: No such file or directory.
[   10.585329] fuse init (API version 7.26)
[   10.626729] i2c /dev entries driver
[   10.695233] systemd-udevd[207]: starting version 215
[   11.108527] gpiomem-bcm2835 3f200000.gpiomem: Initialised: Registers at 0x3f200000
[   11.627465] Bluetooth: Core ver 2.22
[   11.627531] NET: Registered protocol family 31
[   11.627536] Bluetooth: HCI device and connection manager initialized
[   11.627556] Bluetooth: HCI socket layer initialized
[   11.627569] Bluetooth: L2CAP socket layer initialized
[   11.627603] Bluetooth: SCO socket layer initialized
[   11.648621] btbcm: loading out-of-tree module taints kernel.
[   11.648625] btbcm: loading out-of-tree module taints kernel.
[   11.666162] usbcore: registered new interface driver btusb
[   11.668844] Bluetooth: hci0: rtl: examining hci_ver=06 hci_rev=000b lmp_ver=06 lmp_subver=8723
[   11.668859] Bluetooth: hci0: rtl: loading rtl_bt/rtl8723b_fw.bin
[   11.709995] Bluetooth: hci0: rom_version status=0 version=1
[   11.986361] snd_usb_audio: unknown parameter 'nrpacks' ignored
[   11.986374] snd_usb_audio: unknown parameter 'nrpacks' ignored
[   12.018731] usbcore: registered new interface driver snd-usb-audio
[   12.261127] systemd-journald[200]: Received request to flush runtime journal from PID 1
[   12.774161] systemd-journald[200]: Received request to flush runtime journal from PID 1
[   13.958997] random: crng init done
[   14.177269] RTL871X: module init start
[   14.177281] RTL871X: rtl8723bu v4.3.6.11_12942.20141204_BTCOEX20140507-4E40
[   14.177285] RTL871X: rtl8723bu BT-Coex version = BTCOEX20140507-4E40
[   14.362194] RTL871X: rtw_ndev_init(wlan0)
[   14.364011] usbcore: registered new interface driver rtl8723bu
[   14.364018] RTL871X: module init ret=0
[   15.453796] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[   16.275267] RTL871X: RTW_ADAPTIVITY_EN_
[   16.275280] AUTO, chplan:0x20, Regulation:0,0
[   16.275286] RTL871X: RTW_ADAPTIVITY_MODE_
[   16.275290] NORMAL
[   17.002886] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1
[   21.619275] Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
[   22.339674] ip_tables: (C) 2000-2006 Netfilter Core Team
[   22.546843] nf_conntrack version 0.5.0 (15360 buckets, 61440 max)
[   23.254693] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   23.254703] Bluetooth: BNEP filters: protocol multicast
[   23.254723] Bluetooth: BNEP socket layer initialized
[   28.807225] RTL871X: assoc success
[   43.141893] uart-pl011 3f201000.serial: no DMA platform data
[ 5955.806874] FS-Cache: Netfs 'cifs' registered for caching
[ 5955.807249] Key type cifs.spnego registered
[ 5955.807257] Key type cifs.idmap registered

lsusb -t

Code: Select all

/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/5p, 480M
        |__ Port 1: Dev 3, If 0, Class=Vendor Specific Class, Driver=smsc95xx, 480M
        |__ Port 4: Dev 4, If 0, Class=Hub, Driver=hub/2p, 480M
            |__ Port 2: Dev 6, If 3, Class=Human Interface Device, Driver=usbhid, 480M
            |__ Port 2: Dev 6, If 1, Class=Audio, Driver=snd-usb-audio, 480M
            |__ Port 2: Dev 6, If 2, Class=Application Specific Interface, Driver=, 480M
            |__ Port 2: Dev 6, If 0, Class=Audio, Driver=snd-usb-audio, 480M
        |__ Port 5: Dev 5, If 0, Class=Wireless, Driver=btusb, 480M
        |__ Port 5: Dev 5, If 1, Class=Wireless, Driver=btusb, 480M
        |__ Port 5: Dev 5, If 2, Class=Vendor Specific Class, Driver=rtl8723bu, 480M

Re: USB 2.0 Dropped frames

Posted: Tue Jun 04, 2019 5:20 pm
by mikelangeloz
lsusb -v

Code: Select all

Bus 001 Device 005: ID 0bda:b720 Realtek Semiconductor Corp.
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.10
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 ?
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x0bda Realtek Semiconductor Corp.
  idProduct          0xb720
  bcdDevice            2.00
  iManufacturer           1
  iProduct                2
  iSerial                 3
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          236
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower              500mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass        224 Wireless
      bFunctionSubClass       1 Radio Frequency
      bFunctionProtocol       1 Bluetooth
      iFunction               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       224 Wireless
      bInterfaceSubClass      1 Radio Frequency
      bInterfaceProtocol      1 Bluetooth
      iInterface              4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass       224 Wireless
      bInterfaceSubClass      1 Radio Frequency
      bInterfaceProtocol      1 Bluetooth
      iInterface              4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0000  1x 0 bytes
        bInterval               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0000  1x 0 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           2
      bInterfaceClass       224 Wireless
      bInterfaceSubClass      1 Radio Frequency
      bInterfaceProtocol      1 Bluetooth
      iInterface              4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0009  1x 9 bytes
        bInterval               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0009  1x 9 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       2
      bNumEndpoints           2
      bInterfaceClass       224 Wireless
      bInterfaceSubClass      1 Radio Frequency
      bInterfaceProtocol      1 Bluetooth
      iInterface              4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0011  1x 17 bytes
        bInterval               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0011  1x 17 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       3
      bNumEndpoints           2
      bInterfaceClass       224 Wireless
      bInterfaceSubClass      1 Radio Frequency
      bInterfaceProtocol      1 Bluetooth
      iInterface              4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0019  1x 25 bytes
        bInterval               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0019  1x 25 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       4
      bNumEndpoints           2
      bInterfaceClass       224 Wireless
      bInterfaceSubClass      1 Radio Frequency
      bInterfaceProtocol      1 Bluetooth
      iInterface              4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0021  1x 33 bytes
        bInterval               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0021  1x 33 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       5
      bNumEndpoints           2
      bInterfaceClass       224 Wireless
      bInterfaceSubClass      1 Radio Frequency
      bInterfaceProtocol      1 Bluetooth
      iInterface              4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0031  1x 49 bytes
        bInterval               4
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0031  1x 49 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           6
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              2
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x84  EP 4 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x05  EP 5 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x06  EP 6 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               3
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x08  EP 8 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x09  EP 9 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0

Bus 001 Device 006: ID 2772:0230
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 ?
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x2772
  idProduct          0x0230
  bcdDevice            2.10
  iManufacturer           1
  iProduct                3
  iSerial                 0
  bNumConfigurations      2
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          256
    bNumInterfaces          4
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xc0
      Self Powered
    MaxPower                0mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass          1 Audio
      bFunctionSubClass       0
      bFunctionProtocol      32
      iFunction               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol     32
      iInterface              3
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               2.00
        bCategory               8
        wTotalLength           72
        bmControl            0x00
      AudioControl Interface Descriptor:
        bLength                 8
        bDescriptorType        36
        bDescriptorSubtype     10 (CLOCK_SOURCE)
        bClockID               41
        bmAttributes         0x03 Internal programmable Clock
        bmControls           0x07
          Clock Frequency Control (read/write)
          Clock Validity Control (read-only)
        bAssocTerminal          0
        iClockSource            9
      AudioControl Interface Descriptor:
        bLength                 8
        bDescriptorType        36
        bDescriptorSubtype     11 (CLOCK_SELECTOR)
        bUnitID                40
        bNrInPins               1
        baCSourceID( 0)        41
        bmControls           0x03
          Clock Selector Control (read/write)
        iClockSelector          8
      AudioControl Interface Descriptor:
        bLength                17
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             2
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bCSourceID             40
        bNrChannels             2
        bmChannelConfig   0x00000000
        bmControls    0x0000
        iChannelNames          11
        iTerminal               6
      AudioControl Interface Descriptor:
        bLength                18
        bDescriptorType        36
        bDescriptorSubtype      6 (FEATURE_UNIT)
        bUnitID                10
        bSourceID               2
        bmaControls( 0)      0x0000000f
          Mute Control (read/write)
          Volume Control (read/write)
        bmaControls( 1)      0x0000000f
          Mute Control (read/write)
          Volume Control (read/write)
        bmaControls( 2)      0x0000000f
          Mute Control (read/write)
          Volume Control (read/write)
        iFeature                0
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID            20
        wTerminalType      0x0301 Speaker
        bAssocTerminal          0
        bSourceID              10
        bCSourceID             40
        bmControls         0x0000
        iTerminal               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol     32
      iInterface              4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol     32
      iInterface              4
      AudioStreaming Interface Descriptor:
        bLength                16
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           2
        bmControls           0x00
        bFormatType             1
        bmFormats         0x00000001
          PCM
        bNrChannels             2
        bmChannelConfig   0x00000000
        iChannelNames          11
      AudioStreaming Interface Descriptor:
        bLength                 6
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bSubslotSize            4
        bBitResolution         32
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0308  1x 776 bytes
        bInterval               1
        AudioControl Endpoint Descriptor:
          bLength                 8
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bmControls           0x00
          bLockDelayUnits         2 Decoded PCM samples
          wLockDelay              8
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes           17
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Feedback
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       2
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol     32
      iInterface              4
      AudioStreaming Interface Descriptor:
        bLength                16
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           2
        bmControls           0x00
        bFormatType             1
        bmFormats         0x80000000
        bNrChannels             2
        bmChannelConfig   0x00000000
        iChannelNames          11
      AudioStreaming Interface Descriptor:
        bLength                 6
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bSubslotSize            4
        bBitResolution         32
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0308  1x 776 bytes
        bInterval               1
        AudioControl Endpoint Descriptor:
          bLength                 8
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bmControls           0x00
          bLockDelayUnits         2 Decoded PCM samples
          wLockDelay              8
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes           17
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Feedback
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass       254 Application Specific Interface
      bInterfaceSubClass      1 Device Firmware Update
      bInterfaceProtocol      1
      iInterface             10
      Device Firmware Upgrade Interface Descriptor:
        bLength                             9
        bDescriptorType                    33
        bmAttributes                        7
          Will Not Detach
          Manifestation Tolerant
          Upload Supported
          Download Supported
        wDetachTimeout                    250 milliseconds
        wTransferSize                      64 bytes
        bcdDFUVersion                   1.10
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None
      iInterface              0
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      39
         Report Descriptors:
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               8
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          256
    bNumInterfaces          4
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xc0
      Self Powered
    MaxPower                0mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass          1 Audio
      bFunctionSubClass       0
      bFunctionProtocol      32
      iFunction               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol     32
      iInterface              3
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               2.00
        bCategory               8
        wTotalLength           72
        bmControl            0x00
      AudioControl Interface Descriptor:
        bLength                 8
        bDescriptorType        36
        bDescriptorSubtype     10 (CLOCK_SOURCE)
        bClockID               41
        bmAttributes         0x03 Internal programmable Clock
        bmControls           0x07
          Clock Frequency Control (read/write)
          Clock Validity Control (read-only)
        bAssocTerminal          0
        iClockSource            9
      AudioControl Interface Descriptor:
        bLength                 8
        bDescriptorType        36
        bDescriptorSubtype     11 (CLOCK_SELECTOR)
        bUnitID                40
        bNrInPins               1
        baCSourceID( 0)        41
        bmControls           0x03
          Clock Selector Control (read/write)
        iClockSelector          8
      AudioControl Interface Descriptor:
        bLength                17
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             2
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bCSourceID             40
        bNrChannels             2
        bmChannelConfig   0x00000000
        bmControls    0x0000
        iChannelNames          11
        iTerminal               6
      AudioControl Interface Descriptor:
        bLength                18
        bDescriptorType        36
        bDescriptorSubtype      6 (FEATURE_UNIT)
        bUnitID                10
        bSourceID               2
        bmaControls( 0)      0x0000000f
          Mute Control (read/write)
          Volume Control (read/write)
        bmaControls( 1)      0x0000000f
          Mute Control (read/write)
          Volume Control (read/write)
        bmaControls( 2)      0x0000000f
          Mute Control (read/write)
          Volume Control (read/write)
        iFeature                0
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID            20
        wTerminalType      0x0301 Speaker
        bAssocTerminal          0
        bSourceID              10
        bCSourceID             40
        bmControls         0x0000
        iTerminal               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol     32
      iInterface              4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol     32
      iInterface              4
      AudioStreaming Interface Descriptor:
        bLength                16
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           2
        bmControls           0x00
        bFormatType             1
        bmFormats         0x00000001
          PCM
        bNrChannels             2
        bmChannelConfig   0x00000000
        iChannelNames          11
      AudioStreaming Interface Descriptor:
        bLength                 6
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bSubslotSize            4
        bBitResolution         32
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0308  1x 776 bytes
        bInterval               1
        AudioControl Endpoint Descriptor:
          bLength                 8
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bmControls           0x00
          bLockDelayUnits         2 Decoded PCM samples
          wLockDelay              8
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes           17
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Feedback
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval               4
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       2
      bNumEndpoints           2
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol     32
      iInterface              4
      AudioStreaming Interface Descriptor:
        bLength                16
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           2
        bmControls           0x00
        bFormatType             1
        bmFormats         0x80000000
        bNrChannels             2
        bmChannelConfig   0x00000000
        iChannelNames          11
      AudioStreaming Interface Descriptor:
        bLength                 6
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bSubslotSize            4
        bBitResolution         32
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0308  1x 776 bytes
        bInterval               1
        AudioControl Endpoint Descriptor:
          bLength                 8
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
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        bEndpointAddress     0x81  EP 1 IN
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    Interface Descriptor:
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      bInterfaceClass       254 Application Specific Interface
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      Device Firmware Upgrade Interface Descriptor:
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          Will Not Detach
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           ** UNAVAILABLE **
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Bus 001 Device 004: ID 0424:2412 Standard Microsystems Corp.
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
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Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
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  bcdUSB               2.00
  bDeviceClass          255 Vendor Specific Class
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  bcdDevice            2.00
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    bLength                 9
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      Self Powered
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    Interface Descriptor:
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        wMaxPacketSize     0x0010  1x 16 bytes
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Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
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  idVendor           0x0424 Standard Microsystems Corp.
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  Configuration Descriptor:
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      Self Powered
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    Interface Descriptor:
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      Endpoint Descriptor:
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    Interface Descriptor:
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        wMaxPacketSize     0x0001  1x 1 bytes
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Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
  bDeviceProtocol         1 Single TT
  bMaxPacketSize0        64
  idVendor           0x1d6b Linux Foundation
  idProduct          0x0002 2.0 root hub
  bcdDevice            4.09
  iManufacturer           3
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  Configuration Descriptor:
    bLength                 9
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    bNumInterfaces          1
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    bmAttributes         0xe0
      Self Powered
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    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
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      bInterfaceNumber        0
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      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
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        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval              12


Re: USB 2.0 Dropped frames

Posted: Tue Jun 11, 2019 10:51 am
by John Westlake
jdb wrote:
Fri May 17, 2019 9:18 am
Please post
- the full output of dmesg after playback has started and you've had at least one corrupt audio frame
- the output of lsusb -v and lsusb -t
jdb,

Anything interesting from the message dumps you requested?

Re: USB 2.0 Dropped frames

Posted: Tue Jun 11, 2019 1:23 pm
by jdb
USB2.0 isochronous suffers from a subset of the issues that beset full-speed isochronous split transactions.

Typically USB1.1 isochronous transfers are scheduled every full-speed frame and must complete within that frame or the hub will drop the transfer (or response data). This means that the host software (Linux) must meet a scheduling horizon of a few microframes every full-speed frame. For simple devices, this will almost always be met as the definition of "a few" ranges from 3 to 5, for a scheduling horizon of 375-625uS. On the flipside, this horizon needs to be met every full-speed frame, so the dice get rolled 1000 times a second.

For high-speed endpoints, the FIQ code can perform N isochronous transfers in succession where N is the number requested per URB (a function of the driver). Typically drivers request reasonably large numbers for N of 8-32 transfers. At the completion of every N transfers, Linux needs to process the next URB and this imposes a scheduling horizon of 125uS if the endpoint has an interval of 1 microframe.

So for high-speed, the dice get rolled every N microframes but the scheduling requirements are tighter for endpoints with <1ms servicing intervals.

Your device has an endpoint with a 1 microframe servicing interval, so 125uS. This seems excessive for usb-audio applications - is there any scope for increasing the interval?

Re: USB 2.0 Dropped frames

Posted: Tue Jun 11, 2019 2:37 pm
by John Westlake
I'm not sure how much control we have as XMOS as pretty much locked down the USB code on there devices (After the PHY, the USB "interface" is handled by software code in the XMOS hence some very funky programming was required to make it work at USB2.0 speeds).

While the XMOS experiences dropouts other USB class 2.0 audio solutions suffer far worst - so my original question was what is the limitation WRT the RPI USB port (hardware)? Am I correct in saying that the internal USB block does not support DMA transfer hence the need for the CPU to "manually" service the interrupt requests ? - your answer suggesting "This means that the host software must meet a scheduling horizon of a few microframes every full-speed frame" seems to confirm this?

Can the GPU help or one of the ARM cores be dedicated JUST to servicing the USB interrupts?for us its s small price to pay as otherwise the CM3 /RPI is so restricted in HighRes Audio USB applications.

We need a solution that works for all USB audio class 2 device (just as they do with other USB Host devices) - not just modifying the XMOS USB stack.

If its not possible to modify the RPi code to guarantee interrupt handling, is it possible to somehow interface a "Real" USB 2.0 port to the CM3?

As my customers are experiencing dropout issues - I'm being pushed by the software providers to using a SoC from Rockchip or Allwinner H3 - however personally I'd like to stay with RPi due to the mass software ecosystem... and its "British" :)

Re: USB 2.0 Dropped frames

Posted: Tue Jun 11, 2019 4:06 pm
by jdb
The USB hardware supports DMA transfers at the granularity of a single USB transfer. There is no support for chaining transfers together, so each USB transfer results in a interrupt to the CPU which must be handled by software. The only exception to this is high-speed bulk, where the core can transfer large amounts of data to/from a bulk endpoint to/from a contiguous buffer in memory, and interrupt when a short packet is received or transmit of the entire segment is completed.

When I say "scheduling horizon", this is the maximum permitted latency between any interrupt and the host CPU queueing the next USB transfer. All peripheral interrupts are routed in hardware to a single ARM CPU, but the FIQ can be routed to a different CPU (and it is).

Our shipped Linux is not a realtime kernel - interrupt servicing latency is not guaranteed as many places in the kernel disable interrupts while polling hardware / manipulating internal state. There is however a -rt branch being maintained separately within our repository. -rt is "realtime" in the sense that all interrupt handling is threaded and can be preemptible with priority, so assigning USB to a high priority may have a benefit.

https://github.com/raspberrypi/linux/tree/rpi-4.14.y-rt

Porting the rt patches to 4.19 is currently underway but no estimates yet on when maintainers will ask us to incorporate it.

Can you give the rt port a try?

There is no scope for adding a "better" USB host interface - there are no other high-bandwidth bidirectional interfaces capable of interfacing to PHYs or suchlike. Can I ask why USB is a hard requirement over, say, I2S?

Re: USB 2.0 Dropped frames

Posted: Wed Jun 12, 2019 2:22 pm
by John Westlake
WRT I2S we need to support HiRes AUdio and DSD with the DAC being clock Master (so the Audio Data from the RPI is clocked out by the audio device) - otherwise the RPI generated master clock phase nosie is way too high for performance applications.

1. I'm not sure how we can make the I2S a slave (DAC is Audio Clock master)

2. with USB we can support 768KHz @32 bits (IIRC the RPi I2S is limited to 192KHz or some such, broadcom's Documentation on the I2S is very poor)

3. With USB we can support DSD512 (I2S does not support DSD)

4. USB Class 2 Audio drivers are built into Linux

5. Today's interface to External DAC's is via USB (I2S is just an internal Bus)

I'll look into the possibility of implementing a RT operation system - but I can hear the software guys crying already...

Is there any other way with Linux to insure the interrupts are serviced before the USB frames are dropped? I know very little about Linux, could not a ARM core be dedicated JUST to servicing interrupts, or is Linux just not the flexible?

Re: USB 2.0 Dropped frames

Posted: Thu Jun 13, 2019 1:00 pm
by jdb
Noted about I2S - while the peripheral can be driven in slave mode (from an external clock), and can be driven at high bitrates, the required rate is likely too fast for most other I2S interfaces.

There is a possibility that I can slightly mangle isochronous scheduling. For a sequence of isochronous transfers corresponding to a single URB, the FIQ code can handle packet intervals of >1 by using an internal count of how many microframes need to elapse before the next required packet transmission. By pre-emptively queueing a second transfer for the endpoint and offsetting the internal count to "some time in the future" coinciding with when the second URB is supposed to start, two URBs can be pipelined under the control of the latency-perfect FIQ handler. The occasional gaps in Linux scheduling due to interrupt latency could then be hidden in the slack time that we choose.

This does of course require that the device driver submits multiple URBs for an isochronous endpoint, but in practice they cycle through at least 4-8 URBs. For a bidirectional isochronous stream, this would also mean an implicit reservation of 4 of the 8 available hardware transfer channels for a single device - but this is probably a worthwhile tradeoff versus the number of simultaneously supported devices.

Re: USB 2.0 Dropped frames

Posted: Fri Jun 14, 2019 2:23 am
by John Westlake
jdb,

Thank you for your reply, being a hardware guy the the in's and out of the USB protocol is way beyond me :) but I've forward your post to the software guys and see what they make of it :)

Re: USB 2.0 Dropped frames

Posted: Sat Jun 15, 2019 5:08 pm
by John Westlake
jdb,

Thank you for your help with this issue.

After speaking with my software guys I now have a better understanding of the "work around" your proposing - whats the number of USB devices you consider limiting the USB Host Bus to? (We need to consider that USB Hubs need to be factored as USB devices) - we have atleast 2-3 Hubs in the device path, with the LAN9514 being the first).

I'm thinking trying the idea with a limit of 8 USB "devices", maybe more? a typical system:-

1. LAN9514 (How many device's is this with the 4 port hubs and Ethernet LAN)?

2. USB WiFI / BT

3. USB Touch Screen

4. USB Keyboard / touch pad (Such as the Logitec USB Dongle wireless keyboards)

5. USB Thumb Drive / SSD

6. Audio Class 2 Device

7. Dual port Hub

Re: USB 2.0 Dropped frames

Posted: Fri Jun 21, 2019 3:37 pm
by jdb
As long as there are some host channels free, they get rotated between endpoints in a roughly round-robin fashion. The killers are USB bulk-IN endpoints that never return data - for example, GSM modems that are idle. These also typically have multiple bulk endpoints which compounds the problem. The LAN9514 is in the same vein as this, as a host channel will almost always be polling for receive data.

When a host channel is performing a bulk transfer, it will only interrupt the CPU when it has transferred at least some data - if the endpoint never returns data, the host channel is permanently tied up.

Without profiling the exact use case, I can't guarantee a particular setup will or should work - generally you get semi-graceful degradation of performance (i.e. service intervals increase) when there is host channel contention.

Re: USB 2.0 Dropped frames

Posted: Thu Jun 27, 2019 11:00 am
by mikelangeloz
Thanks jdb for your competent replies.

We are really keen to get the situation of USB Audio transfers solved, as this is impacting our customers.

I can impact the frequency of audio dropouts by tinkering with the fiq parameters in cmdline.txt. Those are the current values (which seem to have the best performances of all the combinations I've tried):

Code: Select all

dwc_otg.fiq_enable=1 dwc_otg.fiq_fsm_enable=1 dwc_otg.fiq_fsm_mask=0xF dwc_otg.nak_holdoff=1
Could you please provide any pointer on any other configuration in cmdline.txt that could improve the situation? Is there anything you would suggest elsewhere?

Thanks

Re: USB 2.0 Dropped frames

Posted: Mon Jul 01, 2019 3:03 am
by John Westlake
jbd,

A gentle Ping, is there anyway you can help us here? otherwise the CM3 is very troublesome to use in USB Audio applications -placing a limit on HighRES support (such as DSD256).

Re: USB 2.0 Dropped frames

Posted: Mon Jul 01, 2019 8:54 am
by TS5200
This issue is also really effecting a product I make. I would greatly appreciate if RPI could help assist find a solution.

Re: USB 2.0 Dropped frames

Posted: Tue Jul 02, 2019 12:24 pm
by jdb
We are currently dealing with post-release fallout from Pi4 as people rapidly get their hands on them.

The tentative fix will end up adding another bit in the fiq_fsm_mask parameter that pipelines isochronous transfers but will require testing with hardware that demonstrates the issue. Can you email info@raspberrypi.org to get a dialogue started about providing some representative/test hardware?

Re: USB 2.0 Dropped frames

Posted: Tue Jul 02, 2019 1:01 pm
by John Westlake
jdb,

Thank you, I'll arrange loan units from one of our customers stock (CM3 based Streamer + USB Audio Class 2 DAC) + with a DSD256 test file installed in the streamer memory for your testing.

Are you sure our Email will arrive via the public box, maybe you can PM a direct contact Email.

Re: USB 2.0 Dropped frames

Posted: Tue Jul 02, 2019 2:13 pm
by jdb
The forum DM facility was disabled several months ago. info@ is a monitored address for enquiries.

Re: USB 2.0 Dropped frames

Posted: Sat Jul 06, 2019 2:05 pm
by mikelangeloz
jdb wrote:
Tue Jul 02, 2019 12:24 pm
We are currently dealing with post-release fallout from Pi4 as people rapidly get their hands on them.

The tentative fix will end up adding another bit in the fiq_fsm_mask parameter that pipelines isochronous transfers but will require testing with hardware that demonstrates the issue. Can you email info@raspberrypi.org to get a dialogue started about providing some representative/test hardware?
Just out of curiosity, is this another bit already available in current kernels? If yes, what's the exact parameter, so we can test here locally in the meanwhile?

Re: USB 2.0 Dropped frames

Posted: Mon Jul 08, 2019 9:23 am
by jdb
No, I'm saying that the driver option will be implemented at some point in the future and it will appear as a bit in the bitmask. It's likely to remain disabled by default unless explicitly specified.

@John - I have responded to your email - have you received my reply?

Re: USB 2.0 Dropped frames

Posted: Tue Jul 09, 2019 11:53 am
by John Westlake
jdb,

Sorry, my bad for not pinging you back an "Well received" Email.

I'm arranging for a local UK Co. to send you some hardware directly - with "test files" on a USB flash disk that stress the system, I hope to be able to get some hardware to you for evaluation within a week, basically as soon as it arrives in the UK.

Re: USB 2.0 Dropped frames

Posted: Tue Nov 05, 2019 10:31 am
by John Westlake
Hi jdb,

I understand that our Streamer solution based on the CM3 and DAC with XMOS based UAC2 USB 2.0 Audio interface was sent to you a good couple of months ago now, do you have any updates for us?