I decided to use part of the long holiday weekend to rebuild my workstation at home with the latest Scientific Linux (SL) release.
See solution to my broken audio input issue after the jump.
Having done rebuilds many times before, I already had all my configuration files and data backed up and ready to go. The SL install went smoothly enough, and after some initial annoyance over the still evil NetworkManager (because my machines all have static addresses I just remove it and manually “repair” hosts, resolv.conf and the ifcfg-* files), I got it up and the network and began copying data.
When you’re in a rush to complete a job you sometimes cut corners. Testing every big change you make is usually the first item that gets cut.
In my case I had a fully reconfigured SL 6 workstation with all my original data back in place when I discovered that I couldn’t communicate with the microphone port on my sound card.
Many, many hours later I narrowed the problem to the latest kernel update (2.6.32-131.2.1.el6), that I had installed about halfway through but didn’t subject to a regression test.
As originally installed SL’s sound configuration tool (sndconfig) showed a number of input and output connections, including both my hardware microphone inputs. After the new kernel was installed it only showed a single non-functioning mic and a single non-functioning line input.
Rolling back to the original shipping kernel (2.6.32-71.el6) restored my working mic connections.
The only good news was that this is probably not a permanent issue. I know this because during the two-day nightmare that followed my microphone issue discovery, I had not only re-installed Sci Linux many times, but also tried Fedora 15. Clearly the latter is going for the box o’ icons look that works so well on the 4” screens of smart phones. And yes, now that I’ve had a chance to use it, I do believe that the Gnome Shell is really awful — in fact it has the potential of becoming the Gnome Project’s “Bob”.
I am sure there’s a fix to this issue, but will have to wait for someone on the development team or in the community to figure it out.
For now I’ll continue to tinker as I find the time. One thing I’d like to try tonight it to step through each kernel update since the original release (by installing, via an “rpm -ivh”, just the kernel) and see when things break. That will also give me a chance to see if the nvidia kernel and driver packages from elrepo still work after a kernel update. An exercise in applying the scientific method to Scientific Linux :-)
SOLUTION TO AUDIO INPUT (MIC) ISSUE: After updating my kernel to 2.6.32-71.29.1 without any bad result I went into a holding pattern while looking for a solution. Trawling around this week I noticed a group of kernel module packages for ALSA in Axel Thimm’s (atrpms.net) repository, I decided to update to the latest kernel and see if that might fix the problem. It did.
For the latest SL 6 kernel,
from atrpms.net, and rebooted. After coming back up I checked my microphone and voila! It worked!
(Be careful when mixing and matching packages from different repos, lest you wind up in broken dependency hell. I usually have SL, elrepo, and epel active and enable rpmforge and atrpms when needed.)
If you happen to be running the i686 version of the kernel, there’s a corresponding package for that too.