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by Aydan
Fri Oct 18, 2019 2:44 pm
Forum: Advanced users
Topic: New RT (Real Time) kernel branch
Replies: 65
Views: 16382

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: 224

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: 224

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: 224

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: 250

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: 435

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: 435

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: 513

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: 1188

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: 1188

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: 1188

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: 684

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: 738

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...
by Aydan
Fri Aug 23, 2019 2:19 pm
Forum: General discussion
Topic: unplug anytime ?
Replies: 21
Views: 831

Re: unplug anytime ?

What I said about erase block size still applies to BTRFS. If your BTRFS blocks are smaller than the erase block size (very likely), then the old block and the new block could be located in the same eraseblock, and be both corrupted by a power failure.

Regards
Aydan
by Aydan
Fri Aug 23, 2019 1:21 pm
Forum: General discussion
Topic: unplug anytime ?
Replies: 21
Views: 831

Re: unplug anytime ?

Wear leveling on SD cards is normally of the dynamic kind, meaning it is only done when a block is written to, not like SSDs which will also use blocks that aren't written to for wear leveling and do wear leveling in their spare time. Meaning as long as a block is not written to it stays untouched. ...
by Aydan
Fri Aug 23, 2019 7:38 am
Forum: Troubleshooting
Topic: Raspberry Pi 3B+ - won't boot with keyboard and mouse attached
Replies: 25
Views: 738

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

@retprof:
Does your keyboard have an integrated hub or maybe even an SD-card reader? This might confuse the bootloader.

Could you post "lsusb -t" so we can see if the keyboard has anything strange onboard?

Regards
Aydan
by Aydan
Wed Aug 21, 2019 2:37 pm
Forum: General discussion
Topic: Uses for Raspberry Pi Zero/Zero W?
Replies: 81
Views: 3261

Re: Uses for Raspberry Pi Zero/Zero W?

I recently reactivated a spare original 1B, because I needed something to connect a sensor to and didn't have any other spare Pi lying around, and that felt positively sluggish against the multiple Pi0Ws I have deployed for similar things. Both run Raspian lite, but with the lower CPU frequency I of...
by Aydan
Fri Aug 16, 2019 1:29 pm
Forum: General discussion
Topic: Why moving to 64bit?
Replies: 259
Views: 20972

Re: Why moving to 64bit?

There was a different thread where someone complained about poor SSH speed and i pointed out how the crypto extensions would have made a difference but apparently the userbase was not worth the few cents more per SoC. Yeah, i'd like to know what the real tradeoffs were. There was an early response ...
by Aydan
Mon Aug 12, 2019 1:10 pm
Forum: General discussion
Topic: Pi4 as Desktop computer
Replies: 245
Views: 21366

Re: Pi4 as Desktop computer

@pica200: RPF/T care very much, that's why they give you an optimized Browser called Chromium. If you don't like that, that's your personal preference. I don't like Chromium either, but I won't cry about not having Firefox porper either, I'm happy with ESR. Raspian tracks Debian, and Debian does not...
by Aydan
Wed Aug 07, 2019 11:47 am
Forum: Advanced users
Topic: g_printer module
Replies: 6
Views: 1125

Re: g_printer module

by Aydan
Thu Aug 01, 2019 10:07 am
Forum: Advanced users
Topic: Sanity Check: Multiple Raspberry Pis sharing data and tasked independently
Replies: 7
Views: 366

Re: Sanity Check: Multiple Raspberry Pis sharing data and tasked independently

I think mqtt adds a lot of unnecessary overhead here. I'd start out with simple network sockets. They are supported in Python out of the box, and most other languages have the necessary libraries included as well. For mqtt you'll normally need extra libraries. If it's only two PIs, you can connecte ...
by Aydan
Sat Jul 27, 2019 10:37 am
Forum: Troubleshooting
Topic: Upgraded to Buster - Bind9 Failing to Start
Replies: 12
Views: 593

Re: Upgraded to Buster - Bind9 Failing to Start

is /run mounted properly?
by Aydan
Fri Jul 26, 2019 10:12 am
Forum: Troubleshooting
Topic: Upgraded to Buster - Bind9 Failing to Start
Replies: 12
Views: 593

Re: Upgraded to Buster - Bind9 Failing to Start

Can you start Bind9 manually? if so, then /run has not been mounted when bind starts and the startup sequence is incorrect.
What you could also do is to purge bind9 and reinstall it. Maybe some of the default settings have been changed for Buster.

Regards
Aydan
by Aydan
Tue Jul 23, 2019 3:57 pm
Forum: Advanced users
Topic: Using all 4gb ram with one process
Replies: 16
Views: 851

Re: Using all 4gb ram with one process

I understand some ram is needed for gpu and kernel, but I think this is not the issue? No, it's not, it's a limit of 32-bit linux. Is there a way to increase the max memory for a process or allow for more open ram on the OS(I'm shooting for running 3G for my server)? If the Raspberry has PAE suppor...
by Aydan
Tue Jul 23, 2019 3:51 pm
Forum: Advanced users
Topic: Using all 4gb ram with one process
Replies: 16
Views: 851

Re: Using all 4gb ram with one process

Raspbian is still a 32 bit OS, so process memory space is limited to 2GB per process. I thought a process could access 3GB with 1GB allocated to the OS when using a 32-bit OS with 4GB. Maybe, but the 1GB for the OS would not be visible from the process itself. Also the OS and hardware need PAE supp...

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