Hello Paxton, Em quarta-feira, 8 de dezembro de 2021, às 01:55:13 -03, Paxton Evans escreveu: > Rolling back to linux-libre 5.14.21 (guix > ea7233befb9570cce47e5ca71725b285a580cd22) totally fixes this issue. > > Troubleshooting sound issues on GNU/Linux is such a nightmare that I'm > hoping this list can help me, as I don't really know much about how > sound on our favorite OS really works, and don't have enough information > to file a bug. Can anyone give me pointers on where to start looking? > dmesg on 5.15.6 didn't seem to report anything strange.
I’m not particularly familiar with the moving parts that make sound work either, so I’ll focus on the kernel side of things. My first idea would be trying to boot with the “debug” kernel command line option, which increases the verbosity of kernel messages. Perhaps something helpful will show up in dmesg that way? If not, and if the only change in the working setup vs the non-working setup is the kernel version, then it’s a regression in the kernel. If you are willing to run the upstream Linux kernel on your machine (i.e., the non-libre kernel), the first step would be to run Linux v5.15.6 and see if sound works. If it does, then it’s a bug in linux-libre itself and you should report the problem to them. If it doesn’t, it’s a bug in Linux itself and the most straightforward (but tedious and time-intensive) way to find the kernel commit that caused the bug is to use “git bisect”: https://wiki.gentoo.org/wiki/Kernel_git-bisect That is, assuming that you are comfortable building kernels. You need to use v5.14 as your known-good version not v5.14.21 because your range should be a “straight line” in the version history, and v5.14.x versions branch off from mainline and thus aren’t ancestors of v5.15.x. Also, since you’d be running random kernel commits, it’s important to be aware that there’s a small but non-zero risk of running a bad kernel version which could corrupt something on your system. E.g., not long ago during the v5.12 development cycle there was a filesystem corruption bug: https://www.phoronix.com/scan.php?page=news_item&px=Linux-5.12-Corruption-Fixed You wouldn’t be at risk of hitting that particular bug since your range starts at v5.14, but it’s not inconceivable that there could be something bad in your range (though I’m not aware of anything). The safest way to address that is to run the bisect kernels in a temporary Linux installation on your machine, such as in a USB flash drive rather than on your main Linux installation. -- Thanks, Thiago
