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ALSA: ac97_codec - increase timeout for analog sections to 5 second 

I have a Soundblaster 16PCI. For many years, alsa has had a bug where
not all of the card's controls are detected (many alsa versions,
many kernel versions). In particular, Master Playback Volume is
usually not detected, and so I get no sound or extremely faint sound.
The problem has always been inconsistent: sometimes all of the controls
are detected correctly, and sometimes a partial set is detected. It works
correctly about 10% of the time.

Finally, I got around to tracking down the problem. When the driver
fails, it prints the kernel message "AC'97 0 analog subsections not
ready". This message is generated from the function snd_ac97_mixer()
in ac97_codec.c. The message indicates that the card failed to come
back after reset within the time limit. The time limit is
120 milliseconds.

I tried increasing the time limit to 1 second, and found that this
made the driver work about 70% of the time. I tried increasing it
to 5 seconds, and it now seems to work 100% of the time.

I expect that this change would be completely harmless for
existing cards that work, and would only introduce additional
delay for cards that do not work.

ALSA bug#4032.

Signed-off-by: Steve Soule <sts11dbxr@gmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Steve Soule 2009-12-14 11:06:03 -07:00 committed by Jaroslav Kysela
parent f40542532e
commit f74890277a
1 changed files with 1 additions and 1 deletions
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2
sound/pci/ac97/ac97_codec.c
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@ -2122,7 +2122,7 @@ int snd_ac97_mixer(struct snd_ac97_bus *bus, struct snd_ac97_template *template,
}
/* nothing should be in powerdown mode */
snd_ac97_write_cache(ac97, AC97_GENERAL_PURPOSE, 0);
end_time = jiffies + msecs_to_jiffies(120);
end_time = jiffies + msecs_to_jiffies(5000);
do {
if ((snd_ac97_read(ac97, AC97_POWERDOWN) & 0x0f) == 0x0f)
goto __ready_ok;