Notices by Manawyrm | Sarah (manawyrm@chaos.social)

@foone The GPU searches for the SD card, loads and parses the config.txt file, sets many of the required options, parses device tree overlays, etc. etc.

And yes, it loads kernel and initramfs into memory and then resets/enables the main ARM CPU.

A classic Broadcom move 😹
(with the GPU core being a highly proprietary VideoCore IV architecture)

New blog post:

Executing Linux applications on a Raspberry Pi in less than 3.5s from power-up! 🚀🏎️
(and other power saving tricks)

https://kittenlabs.de/blog/2024/09/01/extreme-pi-boot-optimization/

@ann3nova Do you have special requirements (such as closed captioning, teletext, special timing/interlacing, etc.)? If so: The "older" Pi 3, 4, Zero 2, etc. might be a good choice.
The newer Pi 5 does video a completely different way (generated in the RP1 I/O controller, connected via PCIe), which works as well, but everything is still a bit new and the really cool features/tricks aren't yet supported.

@whitequark @foone yeah, and that looks a lot like delrin, which would fit to milling.

@mntmn Uh, it's been a hot minute since I did this, iirc I used MeshLab to simplify the model to a limited number of polygons.

That helped a lot.

@mntmn not to take on an airplane.

and yes, that's correct for 8 cells. Isn't that awesome?

@whitequark @foone synchronized catgirls :3

@whitequark and some truely atrocious buffer bloat :)

where is Dave Taht when we need him? 😹

@whitequark but 235ms under load according to speedtest.net.

I'm guessing that's already noticable when just surfing the web via the gadget...

@whitequark I didn't actually want to say: "you'll need to fix that", I don't think anyone's going to try and build a router with a glasgow 😹

just mostly a fun real-world example for buffer handling.

@mntmn just compiling, insmod, rmmod'ing kernel modules to do this in a loop would probably also work and be quicker than rebooting... but more work, ofc :)

@mntmn at work I have written a very violent kernel module we lovingly call "holzhammer.ko", which allows you to call functions in kernel space (like the ones to set those tuning parameters) directly, but I'm afraid I can't share that one 😆

@mntmn then that's probably related. yeah, tuning those values "blindly" can be a bit of a tricky job.In the past, I've written a script to change the value, recompile the device-tree and reboot, then test UDP packet loss in a big loop (iperf3/udp). Ideally you do this on a direct link against another NIC which can receive packets with CRC errors.
If you look at the test results of that across the values, it should look somewhat like a bell curve and then you'll get an idea of the best values.

@mntmn are those delays properly tuned?

@foone ASRock, you want ASRock these days. Only ones with somewhat sane firmware ;)

@foone … overheating without reporting that?!

@foone Possible in desktop systems. I really like my NH-D15 and those same Noctua fans on the AMD GPU.

Built that system in 2020 (right before lockdown hit), has been running 24/7 since then, no problems whatsoever.

Highly recommended, just expensive. Awesome peace of mind, though.

@mntmn pmOS wiki is a good resource for mainline Linux support status: https://wiki.postmarketos.org/wiki/Fairphone_5_(fairphone-fp5)

This looks pretty exciting, indeed. Missing audio support could be a platform or device thing, not quite sure. Otherwise looking pretty nice.

Maybe just get a Fairphone 5 and install Linux and give it a shot? :D

@mntmn things I'd try (in this order):
- connect hardware RS232 and configure a console, so you can see kernel output at freeze
- update kernel to master
- update BIOS
- update vBIOS
- reduce PCIe Gen on the GPU
- reduce memory timings to JEDEC defaults (no XMP)
- disable (lowest) C-states
- disable PCIe ASPM
- if running with 4 DIMMs, reduce to 2 DIMMs

@mntmn audio dropouts / cursor stuttering could also be a memory leak. Connect from another machine, have htop open and look at the memory usage. Out of memory condition (especially in the kernel, due to a leak) can cause hangs like this.