Red Hat Bugzilla – Bug 88497
(SOUND VIA_82CXXX)Distorted sound with new AC97 Audio Controller revision
Last modified: 2013-07-02 22:10:45 EDT
Description of problem: Have a few IBM Intellistations here (Type 6836-D1G). IBM choose to replace the motherboards because of some malfunction on the old ones. However, after the replacement the boxes running Linux have problems with the integrated audiocontroller. There is no bass and the treble is distored. Audio works fine on one computer which is running M$ Windows, so this must be a linux driver issue. Same behaviour on rh 7.2 Version-Release number of selected component (if applicable): kernel-2.4.20-9 via82cxxx_audio ac97_codec chipset revision BEFORE mainboard replacement (/proc/pci) Bus 0, device 7, function 5: Multimedia audio controller: VIA Technologies, Inc. AC97 Audio Controller (rev 32). IRQ 5. I/O at 0xdc00 [0xdcff]. I/O at 0xe000 [0xe003]. I/O at 0xe400 [0xe403]. chipset revision AFTER mainboard replacement (/proc/pci) Bus 0, device 7, function 5: Multimedia audio controller: VIA Technologies, Inc. VT82C686 AC97 Audio Controller (rev 80). IRQ 5. I/O at 0xdc00 [0xdcff]. I/O at 0xe000 [0xe003]. I/O at 0xe400 [0xe403]. How reproducible: Is reproducible on all motherboards with this new chipset I think. If you want to, I can probably get the new mainboard's exact part number from IBM if that might help you.
I have had a similar problem on my mainboard. Reason was that the actual codec the AC97 audio used was a Sigmatel which only supported one fixed 48kHz sample rate. That means the sound has to be upsampled by the driver. The linux support for that is not too good. Could you look into the output of dmesg after loading the modules; it should print which actual codec it finds. Then try to find a datasheet for that codec... I solved this by downloading the commercial OSS that Sigmatel offered free licenses for linux users; but later decided to get a new sound card anyway.
dmesg shows the following: Via 686a audio driver 1.9.1 PCI: Found IRQ 5 for device 00:07.5 ac97_codec: AC97 Audio codec, id: 0x4943:0x4511 (ICE1232) via82cxxx: board #1 at 0xDC00, IRQ 5 Enabled Via MIDI I also have quite many instances of: via_audio: ignoring drain playback error -11 and via82cxxx: timeout while reading AC97 codec (0x9A0000)
Thanks for the bug report. However, Red Hat no longer maintains this version of the product. Please upgrade to the latest version and open a new bug if the problem persists. The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases, and if you believe this bug is interesting to them, please report the problem in the bug tracker at: http://bugzilla.fedora.us/