Comment 46 for bug 211644

So I just did a number of things to try to get the sound to work.

For the first step, I booted into the Gutsy 2.6.22 kernel. It worked just fine, so it was a regression between that kernel and the current Hardy 2.6.24 kernel. The mixer is usable, but there is no sound (like described above).

I then compiled a custom 2.6.25.4 kernel from sources at kernel.org with make-kpkg. Once I got the system up, the mixer was usable, but there was no sound.

Ok, so I installed the 2.6.24-16-rt kernel as I saw suggested above in the comments on this bug. It works just fine. This workaround should be listed somewhere if it is not already. I had a really hard time finding this information. I am also really curious why doing this fixes the problem.

I didn't stop there, however; I also found bug #191859, which had a patch for a file in the source[1]. I looked around and also found a patch[2] that has been applied to the post-2.6.25 dev kernel. After corresponding with the author of [1], I found that the patch at [2] was actually the full fix and that the line from [1] that doesn't appear in [2] (the line containing 0x0a) shouldn't be in the fix.

As a matter of personal interest, I grepped the patches in the linux-2.6.24/debian/binary-custom.d/rt/patchset/ directory (in the source package for the 2.6.24 kernel) and didn't see a mention of patch_sigmatel.c file that is the location of the fix. Why does the -rt (and not the -generic) kernel work? Is there a patch somewhere else?

My laptop and my future father-in-law's laptop are affected by this bug. His experience was extremely positive with Ubuntu until this little mishap. Thankfully, he is fairly technical and is willing to do a lot of troubleshooting, but I wouldn't want to have to do such troubleshooting with a complete novice.

Finally, I wanted to make it known that I am willing to help out (testing, etc.) with getting a package out that contains the fix for this issue since it doesn't look like even testing kernels (2.6.24-17.31 was the latest I could find in the Ubuntu repository) has the fix. What can I do to help this effort of getting a fixed kernel module out?

[1]http://launchpadlibrarian.net/12092018/0001-UBUNTU-Adjust-quirk-for-snd-hda-intel-on-Dell-lapto.patch
[2]http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blobdiff;f=sound/pci/hda/patch_sigmatel.c;h=70c56945975869580ba2cdfd0c1275f7e7ca16be;hp=a31155d41405afdda82e2bd70067681f45516914;hb=7989fba979daea99285079dc0099ab658e4db759;hpb=4451089e2aafba87d7574e27c839895131a80293

Thanks,
wt