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by jdb
Wed Nov 25, 2020 2:17 pm
Forum: Troubleshooting
Topic: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)
Replies: 11
Views: 346

Re: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)

There are 2 crashes in skb_release_data which is a network-related function.

Does the crash still occur (or change behaviour) if you run the offending command with the network cable disconnected?
by jdb
Wed Nov 25, 2020 1:09 pm
Forum: Troubleshooting
Topic: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)
Replies: 11
Views: 346

Re: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)

Far as I know there is no advantage to using the dwc2 driver over the default dwc one when any model Pi is operating as a USB host. In fact there was a time when it not recommended, performance as a host was worse with dwc2, IIRC it was an issue related to interrupts. When not using the Pi as a USB...
by jdb
Wed Nov 25, 2020 12:04 pm
Forum: Troubleshooting
Topic: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)
Replies: 11
Views: 346

Re: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)

I would suggest taking a photo of the screen and uploading to an image hosting site.
by jdb
Tue Nov 24, 2020 10:57 am
Forum: Troubleshooting
Topic: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)
Replies: 11
Views: 346

Re: dtoverlay=dwc2 causing errors and kernel OOPS on Raspberry Pi 1 Model B (256 MB RAM)

Your stack traces are incomplete. I would recommend removing any "kdb" or "kgdboc" parameters from cmdline.txt as the kernel is waiting for console input to print the rest of the trace (which is going to be hard because USB has gone away). That said, it does look a lot like memory corruption (use-af...
by jdb
Thu Nov 19, 2020 9:18 pm
Forum: General discussion
Topic: Hardware problem
Replies: 5
Views: 330

Re: Hardware problem

It's a bandpass filter for the wireless antenna.

The wireless interface will probably work without it, but with degraded reception and may have out-of-band emissions when transmitting.

I'd recommend not using it as a Zero W and instead using it as a Zero.
by jdb
Thu Nov 19, 2020 9:01 pm
Forum: General discussion
Topic: No analog sound through an external amplifier on Rpi 3B v1.2
Replies: 31
Views: 755

Re: No analog sound through an external amplifier on Rpi 3B v1.2

Wow this thread is quite the ride. And disappointing - how much more effort is it to sling mud in typed form than it is to just ignore this thread? If I'm not mistaken firmware for the RPI3 and 4 now switches off the PWM engines needed for analog sound to save some energy, and you have to purposeful...
by jdb
Tue Nov 17, 2020 12:56 pm
Forum: Troubleshooting
Topic: Noisy Raspberry (19300 Hz sound emission)
Replies: 5
Views: 194

Re: Noisy Raspberry (19300 Hz sound emission)

Are you using the same power supply between the noisy boards and the "quiet" board?
by jdb
Wed Nov 11, 2020 3:37 pm
Forum: Beginners
Topic: Official power supply browns out with RPi 4B, voltage specifications mismatched
Replies: 19
Views: 627

Re: Official power supply browns out with RPi 4B, voltage specifications mismatched

Your reported symptom is "red light blinks when the board is rebooted" - which I have explained is expected behaviour. I also note that your board works correctly after reboot. Yet we somehow go from that (working) scenario to declarations of incompetence because you're comparing worst-case toleranc...
by jdb
Wed Nov 11, 2020 1:54 pm
Forum: Beginners
Topic: Official power supply browns out with RPi 4B, voltage specifications mismatched
Replies: 19
Views: 627

Re: Official power supply browns out with RPi 4B, voltage specifications mismatched

The PWR LED is also under software control, and blinks briefly before the watchdog reset mechanism is called.

Have you actually measured the voltage on the 5V pins on the GPIO header?
by jdb
Wed Nov 11, 2020 10:39 am
Forum: Compute Module
Topic: CM4 doubts
Replies: 13
Views: 665

Re: CM4 doubts

The encoder is connected to a single-channel DAC, so of the available options, only composite video makes sense.
by jdb
Sat Nov 07, 2020 6:40 pm
Forum: Beginners
Topic: Raspberry pi 400
Replies: 125
Views: 4541

Re: Raspberry pi 400

Aren't Cherry switches supposed to be tactile rather than smooth? Some are, some aren't depends on which version of Cherry switch. I can't keep track of all the options, but I think it's the "Brown" switches are somewhere in between non-clicky and very clicky. Take your pick - https://www.cherrymx....
by jdb
Sat Nov 07, 2020 6:22 pm
Forum: Beginners
Topic: I'm a beginner
Replies: 15
Views: 543

Re: I'm a beginner

OP obviously got hit with the ban stick for that comical but insulting chain of posts.
Locking. What an odd way to approach a problem.
by jdb
Fri Nov 06, 2020 8:15 pm
Forum: Raspberry Pi 400
Topic: The Raspberry Pi 400 thread!
Replies: 893
Views: 38569

Re: The Raspberry Pi 400 thread!

What I want to know is... Could one use the Pi 400 as a regular keyboard to a PC or whatever? Probably, if the USB-C power socket is the same as on a 4B in the sense that it can function as a USB device. But same issue as with a 4B of getting enough power into the socket while connected to a USB ho...
by jdb
Mon Nov 02, 2020 4:21 pm
Forum: Troubleshooting
Topic: rtl_usb: Urb has error status 0xFFFFFFB9
Replies: 2
Views: 98

Re: rtl_usb: Urb has error status 0xFFFFFFB9

Urgh. This is a bit pants https://elixir.bootlin.com/linux/v5.4.74/source/drivers/net/wireless/realtek/rtlwifi/usb.c#L852 1. The status should be parsed as a signed int, not converted to hex. 2. Certain URB error codes *need* to be handled by the driver - as they report endpoint stalls as well as di...
by jdb
Mon Nov 02, 2020 3:51 pm
Forum: Raspberry Pi 400
Topic: The Raspberry Pi 400 thread!
Replies: 893
Views: 38569

Re: The Raspberry Pi 400 thread!

Network boot completely invalidates the "SD cards are insecure" argument. In a thin-client corporate environment, you want to never have to physically *go* to a device to provision it, or have to track things like what software is on which SD card. As James says, the client will typically run a web ...
by jdb
Mon Nov 02, 2020 1:09 pm
Forum: Raspberry Pi 400
Topic: The Raspberry Pi 400 thread!
Replies: 893
Views: 38569

Re: The Raspberry Pi 400 thread!

but which peripherals are even unused enough to reduce the heat generation when gated? is it just things like DSI/CSI being turned off, since the pi400 lacks those connectors? or is it features the public doesn't even know of, that you cant name? Remember this gating can turn on and off many times ...
by jdb
Mon Nov 02, 2020 12:56 pm
Forum: Troubleshooting
Topic: Pi 4B: UVC cameras stop sending frames after random interval
Replies: 14
Views: 582

Re: Pi 4B: UVC cameras stop sending frames after random interval

Hang on, if I search for the vid:pid of the cameras in question, I get several hits about them randomly disconnecting - not just on Pi 4s. Pi 4 appears to be different in that the entire downstream tree gets disconnected and not just the device. Key phrase was "ARC international" which appears to be...
by jdb
Mon Nov 02, 2020 12:36 pm
Forum: Raspberry Pi 400
Topic: The Raspberry Pi 400 thread!
Replies: 893
Views: 38569

Re: The Raspberry Pi 400 thread!

Uh, what's so hard to understand about the clock frequency thing? The Raspberry Pi 4 is validated to work at 1.5 GHz. That is, the manufacturer tests the chips and guarantees that they work correctly up to 1.5 GHz. The Raspberry Pi 400 is validted to work at 1.8 GHz. That is, the manufacturer tests...
by jdb
Fri Oct 30, 2020 10:42 am
Forum: Advanced users
Topic: Analogue audio redux
Replies: 114
Views: 39793

Re: Analogue audio redux

Latest rpi-update firmware avoids running the audio resampling on the same core as deinterlace/camera tasks. It should fix your use-case (and others) but there is the possibility that other more obscure sets of tasks may interfere.
by jdb
Thu Oct 29, 2020 5:18 pm
Forum: Troubleshooting
Topic: Analog audio stops working randomly
Replies: 6
Views: 197

Re: Analog audio stops working randomly

The userspace driver in the rpi_ws281x library changes the PWM clock from 107MHz to 24KHz. There's not much the firmware can do about that. There shouldn't be a need to clobber the PWM frequency on Pi 4 at all - ws2812 bashers typically use the PWM peripheral in serialiser mode which means you can ...
by jdb
Fri Oct 23, 2020 11:43 am
Forum: Troubleshooting
Topic: Pi 4B: UVC cameras stop sending frames after random interval
Replies: 14
Views: 582

Re: Pi 4B: UVC cameras stop sending frames after random interval

I'm out of ideas at this point. Have you read the UVC FAQ at http://www.ideasonboard.org/uvc/faq/ ? Disabling USB autosuspend, adding quirks or reducing USB bandwidth might be worth trying according to the instructions on that page. Disabling autosuspend might be worth investigating indeed. UVC came...
by jdb
Thu Oct 22, 2020 10:20 am
Forum: Compute Module
Topic: CM4 launched
Replies: 149
Views: 5145

Re: CM4 launched

IIRC graphics controllers are pretty unusual in taking up huge chunks of address space to address the huge amounts of on-card memory they have. Yeah, in this case it looks like it's having trouble allocating more than 32MB: BAR 9 size 0x0c000000 ≈ 200 MB (fails) BAR 1 size 0x08000000 ≈ 128 MB (fail...
by jdb
Wed Oct 21, 2020 7:42 pm
Forum: Compute Module
Topic: What is the point of using CM4 instead of Pi4?
Replies: 28
Views: 1061

Re: What is the point of using CM4 instead of Pi4?

raspberry_user wrote:
Wed Oct 21, 2020 3:25 pm
I read that the CM4 is faster from one of the reviewers. Don't remember who that is.
Fortunately, you don't have to remember.

Your browser history saves that information for you.

What website lead you to form the opinion that "CM4 is faster"?
by jdb
Tue Oct 20, 2020 7:25 am
Forum: Compute Module
Topic: Then there's the *other* feature...
Replies: 35
Views: 1023

Re: Then there's the *other* feature...

cjan wrote:
Tue Oct 20, 2020 1:08 am
I/O board cheap but looks large and ugly, wait 3rd party board.
Thanks for the detailed feedback, I'll be sure to pass it along
by jdb
Wed Oct 14, 2020 1:46 pm
Forum: Advanced users
Topic: Configuring audio out to use only one PWM port
Replies: 14
Views: 2970

Re: Configuring audio out to use only one PWM port

The firmware analogue audio driver will always configure both PWM channels. This isn't going to change. If you want "mono" output, then open the ALSA sink with 1 audio channel configured in your PCM format - this will cause it to do "dual mono" output on both PWM channels, and you can ignore the one...

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