[svlug] ALSA woes with via82xx

[Brian J. Tarricone]

Hi all,

About 2 years ago I built a PVR/HTPC.  The DFI (8M800 MLVF)
motherboard has an integrated VIA 8237 audio chipset, which appears to
be supported by the snd-via82xx driver, though I could never get it
working.  After hours of fiddling, I eventually gave up and bought a
well-supported Turtle Beach card, with which I've been able to use a
coaxial digital output to my stereo receiver.

I was poking at the motherboard for unrelated reasons the other day,
and I noticed that it has a S/PDIF header on it.  So presumably I could
get the same digital out from the integrated sound if I were to buy a
bracket with connectors for it (along with getting the drivers working,
of course).  I'm considering leaving the box on 24/7 as a file server
after retiring another computer I have, so I'm looking to free up a PCI
slot for an extra SATA controller, and to just generally try to reduce
power usage.

So, I decided to give the integrated sound a try again, but I'm having
no more success than last time.  Various googling seems to show that
this chipset is still somewhat problematic, that ALSA support for it is
a bit hit-or-miss, and there are often some manual driver tweaks needed
to get things going.  I've tried all the different combinations of the
ac97_quirk and dxs_support module parameters, as well as fiddling
endlessly with all the various mixer elements.  Playing a .wav file
using 'aplay' appears to work, but I get no sound out of the speakers.
I'm currently trying bleeding-edge kernel 2.6.21 (with Gentoo
patches, none of which should be related), though I've tried several
different kernels in the box over the past 2 years going as far back as
2.6.10.

Right now I'm just trying to get an analog signal out of the front
outputs.  I'd rather not shell out any cash for the S/PDIF connector
bracket until I can at least get that working.

Does anyone have any experience with this chipset?  Any similar
problems, or hints on how to get it to work properly?

	-brian

P.S.  Some related output that might be useful:

lspci -vvv output for the sound card:

00:11.5 Multimedia audio controller: VIA Technologies, Inc.
VT8233/A/8235/8237 AC97 Audio Controller (rev 60) Subsystem: DFI Inc
Unknown device 3001 Control: I/O+ Mem- BusMaster- SpecCycle- MemWINV-
VGASnoop- ParErr- Stepping- SERR- FastB2B- Status: Cap+ 66MHz- UDF-
FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Interrupt: pin C routed to IRQ 21 Region 0: I/O ports at eb00 [size=256]
        Capabilities: [c0] Power Management version 2
                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA
PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 PME-Enable- DSel=0 DScale=0
PME-

$ cat /proc/asound/cards
 0 [V8237          ]: VIA8237 - VIA 8237
                      VIA 8237 with CMI9761A+ at 0xeb00, irq 21
$ cat /proc/asound/pcm 
00-01: VIA 8237 : VIA 8237 : playback 1 : capture 1
00-00: VIA 8237 : VIA 8237 : playback 4 : capture 1

$ amixer
Simple mixer control 'Master',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 31 [100%] [0.00dB] [on]
  Front Right: Playback 31 [100%] [0.00dB] [on]
Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 31 [100%] [-48.00dB] [on]
  Front Right: Playback 31 [100%] [-48.00dB] [on]
Simple mixer control 'Surround',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [on]
  Front Right: Playback [on]
Simple mixer control 'Surround Jack Mode',0
  Capabilities: enum
  Items: 'Shared' 'Independent'
  Item0: 'Shared'
Simple mixer control 'Center',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 31
  Mono: Playback 31 [100%] [0.00dB] [on]
Simple mixer control 'LFE',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 31
  Mono: Playback 0 [0%] [-46.50dB] [off]
Simple mixer control 'Line',0
  Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 0 [0%] [-34.50dB] [off] Capture [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off] Capture [off]
Simple mixer control 'CD',0
  Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 0 [0%] [-34.50dB] [off] Capture [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off] Capture [off]
Simple mixer control 'Mic',0
  Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 0 [0%] [-34.50dB] [off] Capture [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off] Capture [off]
Simple mixer control 'Mic Boost (+20dB)',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Mic Select',0
  Capabilities: enum
  Items: 'Mic1' 'Mic2'
  Item0: 'Mic1'
Simple mixer control 'Video',0
  Capabilities: cswitch cswitch-exclusive
  Capture exclusive group: 0
  Capture channels: Front Left - Front Right
  Front Left: Capture [off]
  Front Right: Capture [off]
Simple mixer control 'Phone',0
  Capabilities: cswitch cswitch-exclusive
  Capture exclusive group: 0
  Capture channels: Front Left - Front Right
  Front Left: Capture [off]
  Front Right: Capture [off]
Simple mixer control 'IEC958',0
  Capabilities: pswitch pswitch-joined cswitch cswitch-joined
  Playback channels: Mono
  Capture channels: Mono
  Mono: Playback [off] Capture [off]
Simple mixer control 'IEC958 Capture Monitor',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 Capture Valid',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 Output',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 Playback AC97-SPSA',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 3
  Mono: 0 [0%]
Simple mixer control 'IEC958 Playback Source',0
  Capabilities: enum
  Items: 'AC-Link' 'ADC' 'SPDIF-In'
  Item0: 'AC-Link'
Simple mixer control 'PC Speaker',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 15
  Mono: Playback 0 [0%] [-45.00dB] [off]
Simple mixer control 'Aux',0
  Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 0 [0%] [-34.50dB] [off] Capture [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off] Capture [off]
Simple mixer control 'Mono Output Select',0
  Capabilities: enum
  Items: 'Mix' 'Mic'
  Item0: 'Mix'
Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch cswitch-joined
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 15
  Front Left: Capture 0 [0%] [0.00dB] [on]
  Front Right: Capture 0 [0%] [0.00dB] [on]
Simple mixer control 'Mix',0
  Capabilities: cswitch cswitch-exclusive
  Capture exclusive group: 0
  Capture channels: Front Left - Front Right
  Front Left: Capture [on]
  Front Right: Capture [on]
Simple mixer control 'Mix Mono',0
  Capabilities: cswitch cswitch-exclusive
  Capture exclusive group: 0
  Capture channels: Front Left - Front Right
  Front Left: Capture [off]
  Front Right: Capture [off]
Simple mixer control 'Channel Mode',0
  Capabilities: enum
  Items: '2ch' '4ch' '6ch'
  Item0: '2ch'
Simple mixer control 'DAC Clock Source',0
  Capabilities: enum
  Items: 'AC-Link' 'SPDIF-In' 'Both'
  Item0: 'AC-Link'
Simple mixer control 'External Amplifier',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Input Source Select',0
  Capabilities: enum
  Items: 'Input1' 'Input2'
  Item0: 'Input1'
Simple mixer control 'Input Source Select',1
  Capabilities: enum
  Items: 'Input1' 'Input2'
  Item0: 'Input2'