Arch Linux

Emphrygian

Member

Registered: 2007-04-18

Posts: 27

Sound broken since upgrade from 2.6.29

I wasn't sure if I should post this here or in the multimedia forum. Anyway...

I have an Echo Audio Mia-midi soundcard and sound hasn't been working properly for me since upgrading from 2.6.29. Both 2.6.30 and 2.6.31 share the same issue and reverting to 2.6.29 always solves the problem. It seems some driver infrastructure has changed, because the two "Line out" level meters are not available in alsamixer anymore. Instead I have VU-meters for front, rear, center, woofer and side. These can't be set however, and seem to have no impact on the output (they are sometimes set to 100% and sometimes to 0%, but output is silent in both cases).

Running echomixer (an Echo Audio specific mixer in alsa-tools) and playing sound shows that there is sound playing at full volume at the subdevice channels, but the "final" output is silent, even though all output channels are set at their proper values, including the output mixer. Raising the monitor mixer, effectively forwarding the input channels to the output works as it should, so as far as I can tell, the issue concerns the software/driver output to the soundcard.

I've tried everything I can think of to solve this, but nothing seems to help. I've run an alsa debug script in both 2.6.29 and 2.6.31, but the only difference worth noting that I can find is connected to the line out level meters. In 2.6.29:

Simple mixer control 'Line',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right - Rear Left - Rear Right
  Limits: Playback -128 - 6
  Mono:
  Front Left: Playback 0 [96%] [0.00dB]
  Front Right: Playback 0 [96%] [0.00dB]
  Rear Left: Playback 0 [96%] [0.00dB]
  Rear Right: Playback 0 [96%] [0.00dB]
.......
.......
state.Mia {
    control.1 {
        comment.access 'read write'
        comment.type INTEGER
        comment.count 4
        comment.range '-128 - 6'
        comment.dbmin -12800
        comment.dbmax 600
        iface MIXER
        name 'Line Playback Volume'
        value.0 0
        value.1 0
        value.2 0
        value.3 0
    }

Both of these parts are missing from the output in 2.6.31.

I don't know what to do next. Any help would be greatly appreciated.