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by Aydan
Wed Dec 18, 2019 4:18 pm
Forum: Advanced users
Topic: Disable 10ms interrupt on core 2&3
Replies: 3
Views: 790

Re: Disable 10ms interrupt on core 2&3

@weishisky
what you try to do is a device driver, so implement it as a device driver in the kernel (as a kernel module), not in userspace.
For reference look at the onewire gpio driver for the raspi.

Regards
Aydan
by Aydan
Thu Dec 12, 2019 1:58 pm
Forum: HATs and other add-ons
Topic: PoE HAT for RPi Zero
Replies: 0
Views: 157

PoE HAT for RPi Zero

I'm thinking about making a PoE HAT for the RPi Zero, to make PoE IP cameras. If I use the LAN9512 Ethernet/USB Controller and have a µSD with bootcode.bin in the RPi0, would that be enough to allow network booting like on the RPi3? Is any special pinstrap configuration needed for the LAN9512? I hav...
by Aydan
Thu Dec 12, 2019 1:17 pm
Forum: General discussion
Topic: [Solved] Annoying feature of 'apt-get uprgade'
Replies: 42
Views: 2027

Re: Annoying feature of 'apt-get uprgade'

But if 'apt' simply overwrites user modified configuration files, or if it doesn't, doesn't offer a choice, that's potentially more problematic than the issue with 'apt-get', arguably even less fit for purpose. I think apt overwrites config files only when they have not been changed by the user. Ot...
by Aydan
Tue Dec 10, 2019 10:55 am
Forum: Troubleshooting
Topic: analog Sound Raspberry PI 4 is mono, not stereo
Replies: 47
Views: 2008

Re: analog Sound Raspberry PI 4 is mono, not stereo

@RossDv8: Are you sure you don't have a broken audio cable?

Your description of sometimes it works, sometime it doesn't, sounds to me like an intermittent connection of the right channel.

Regards
Aydan
by Aydan
Wed Dec 04, 2019 11:19 am
Forum: Troubleshooting
Topic: mmcblk0 unnaccessable
Replies: 10
Views: 422

Re: mmcblk0 unnaccessable

So I went and did the code using sda: sudo xzcat genpi64.img.xz > /dev/sda && sync and got this result: bash: /dev/sda: Permission denied What happened?? There's two things why it doesn't work: #1 is sda1 is mounted, as RonR has said. #2 is that the output redirection (">") to /dev/sda does not run...
by Aydan
Wed Nov 20, 2019 1:07 pm
Forum: Advanced users
Topic: Can I pass Data through a Relay.
Replies: 2
Views: 257

Re: Can I pass Data through a Relay.

I want to connect two Pi's to the same SD card and use a relay to signal when one Pi will write an image to the SD card and then signal when the other Pi will boot using the written image. My question here is: "what do you want to achieve with this?" It is technicaly possible to switch the SD card ...
by Aydan
Wed Nov 13, 2019 12:28 pm
Forum: Troubleshooting
Topic: rPi Zero W HDMI cuts in and out before dying
Replies: 1
Views: 88

Re: rPi Zero W HDMI cuts in and out before dying

This looks like a thermal problem. When it heats up, the problem intensifies. If you haven't done so already, enable ssh and a wlan connection to check if the Pi is still accessible over ssh when the display cuts out. If it is, then increase the hdmi_drive in config.txt. This may fix the problem. Re...
by Aydan
Wed Nov 13, 2019 12:22 pm
Forum: Troubleshooting
Topic: Upgrade to buster partial failure (i think)
Replies: 6
Views: 363

Re: Upgrade to buster partial failure (i think)

If you rebooted after the update, and the OS is more or less up and running, the first thing to try would be to run "apt install --fix-broken". There may be a message to run "dpkg-reconfigure --all". If that is tha case, run the command. If that fails, check the journal what exactly failed. Regards ...
by Aydan
Mon Nov 04, 2019 6:08 pm
Forum: General discussion
Topic: Nightly email hints at trouble to come...
Replies: 5
Views: 794

Re: Nightly email hints at trouble to come...

The installed packages are likely to be fine, as once written, they remain untouched. Your collected data is going to be at risk here, and I'd check the integrity of that ASAP, then back it all up somewhere safe. That assumption is fundamentally wrong for flash storage due to the size of erase bloc...
by Aydan
Mon Nov 04, 2019 1:36 pm
Forum: General discussion
Topic: Nightly email hints at trouble to come...
Replies: 5
Views: 794

Re: Nightly email hints at trouble to come...

You can check the intergrity of files installed by packages using "debsums". Checking files which are not part of a deb-package will be harder. You could save the checksum for each file in an xattr of said file, and have a script run over all files periodically comparing the saved checksum against t...
by Aydan
Thu Oct 24, 2019 1:06 pm
Forum: Troubleshooting
Topic: Eth1 management access problem
Replies: 5
Views: 210

Re: Eth1 management access problem

@labnario:
please check dmesg for undervoltage warnings and USB disconnects.

The problem could be undervoltage on the USB Ethernet adapter, or the adapter has a thermal problem and malfunctions after warming up.

Regards
Aydan
by Aydan
Wed Oct 23, 2019 9:54 am
Forum: Advanced users
Topic: RP4 Cluster Hardware?
Replies: 16
Views: 1382

Re: RP4 Cluster Hardware?

Ya the network boot is quite intriguing and I would have to assess how to net boot for more than 255 items (subnet). You can have a subnet larger than class c (mask 255.255.255.0) a subnet with mask 255.255.248.0 will allow 1022 nodes and so on. You can basically have subnets up to class A if you w...
by Aydan
Fri Oct 18, 2019 2:44 pm
Forum: Advanced users
Topic: New RT (Real Time) kernel branch
Replies: 65
Views: 20107

Re: New RT (Real Time) kernel branch

#1 you can get a root shell with "sudo -i", no need for a root pw.
#2 you can prevent package updates by "holding" a package via "apt-mark hold <package-name>"
the package in this case is "raspberrypi-kernel"

Regards
Aydan
by Aydan
Thu Sep 26, 2019 3:21 pm
Forum: Advanced users
Topic: Detecting Gadget Mode activity
Replies: 7
Views: 366

Re: Detecting Gadget Mode activity

Depending on the performance you need, the python implementation might be too slow.

Good find, by the way.

Regards
Aydan
by Aydan
Thu Sep 26, 2019 3:05 pm
Forum: Advanced users
Topic: Detecting Gadget Mode activity
Replies: 7
Views: 366

Re: Detecting Gadget Mode activity

lookee here: https://github.com/libfuse/libfuse/blob/master/example/passthrough.c fuse has been mainline for a long time and many things use it, e.g. gnome's gvfs for samba and so on. One caveat is that fuse mounts are by default only accessible by the mounting user, not even root has access. Can be...
by Aydan
Thu Sep 26, 2019 1:54 pm
Forum: Advanced users
Topic: Detecting Gadget Mode activity
Replies: 7
Views: 366

Re: Detecting Gadget Mode activity

This might be the roundabout way, but if you can share an image file instead as MSD instead of a partition, then you could mount the partition where the image file resides with a modified fuse passthrough shim. This will allow you to monitor any read or write accesses to the image file.

Regards
Aydan
by Aydan
Thu Sep 19, 2019 2:58 pm
Forum: Troubleshooting
Topic: What prevents a 'sudo reboot' ?
Replies: 6
Views: 359

Re: What prevents a 'sudo reboot' ?

So seems that it's the Python code not being killed. It's launched with nothing special - /usr/bin/python /home/pi/apps/dpf/clk.py & There's no weird error trapping in that, just a try-except KeyboardInterrupt which has never caused problems in the past with similar Python code. Are you using threa...
by Aydan
Fri Sep 13, 2019 2:32 pm
Forum: Device Tree
Topic: Make pin low active on PCA9554
Replies: 2
Views: 1813

Re: Make pin low active on PCA9554

Hmm, OK, thanks for the clarification.
The PCA9554 actually does support per pin inversion via it's config register, but I couldn't figure out if the driver actually uses this except for optionally inverting all pins during init.
I suppose I'll do the pinconfig in my application.

Thanks
Aydan
by Aydan
Fri Sep 13, 2019 12:11 pm
Forum: Device Tree
Topic: Make pin low active on PCA9554
Replies: 2
Views: 1813

Make pin low active on PCA9554

I made a devicetree overlay for the ClusterHAT which uses a PCA9554. One of the pin functions is low active, but I couldn't figure out hor to add that into the device tree. Here's the file: /dts-v1/; /plugin/; / { compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709"; fragment@0 { target = <&i...
by Aydan
Mon Sep 02, 2019 1:52 pm
Forum: General discussion
Topic: reset a frozen system remotely
Replies: 14
Views: 772

Re: reset a frozen system remotely

Yes it does, but if you can't even get the kernel and some services loaded, then an external reset won't help you either. The on chip watchdog is activated by the first access to it and cannot be stopped again. This makes it ideal to reset a hung system. It will do nothing for a system that does not...
by Aydan
Sat Aug 31, 2019 1:11 pm
Forum: Python
Topic: Problem with closing the terminal processes
Replies: 19
Views: 1756

Re: Problem with closing the terminal processes

Actually I tried using subprocess but it is sequential. I have a python flask server script to run, a terminal command to port forward and a bash file to start Alexa sample app. Subprocess is not inherently sequential. Depends how you use it. I usually use subprocess.popen. If your child process ge...
by Aydan
Fri Aug 30, 2019 2:34 pm
Forum: Python
Topic: Problem with closing the terminal processes
Replies: 19
Views: 1756

Re: Problem with closing the terminal processes

Ok, so I should use subprocess inseated os.system to call sudo bash start.sh and sudo bash start.sh. But in the start.sh file there are commands to run that 3 terminal with the individual process so How will I find which process is of which? As I said above I am getting 3 python process running and...
by Aydan
Fri Aug 30, 2019 1:09 pm
Forum: Python
Topic: Problem with closing the terminal processes
Replies: 19
Views: 1756

Re: Problem with closing the terminal processes

I see you are using os.system.
I'd suggest using subprocess instead.
This way you can collect the process objects into a list, and then signal them when you're done.

I'd also suggest looking at e.g. espeak for TTS so you don#t have to save the audio file before playing it.

Regards
Aydan
by Aydan
Wed Aug 28, 2019 9:31 am
Forum: Advanced users
Topic: Multiple Zeros on Pi4
Replies: 5
Views: 827

Re: Multiple Zeros on Pi4

You are probably having a routing problem.
Please provide the output of "ip addr show" from your Pi4
If you have both zeros on the same subnet, and have not bridged the networks, then the packets will not be routed correctly.

Regards
Aydan
by Aydan
Sun Aug 25, 2019 7:53 am
Forum: Troubleshooting
Topic: Raspberry Pi 3B+ - won't boot with keyboard and mouse attached
Replies: 25
Views: 1134

Re: Raspberry Pi 3B+ - won't boot with keyboard and mouse attached

Responding to Aydan's request to post the output from lsusb -t for the keyboard: pi@raspberrypi:~ $ ls Desktop Downloads Music Public Videos Documents MagPi Pictures Templates pi@raspberrypi:~ $ lsusb -t /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M |__ Port 1: Dev 2, If 0, Class...

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