[alsa-devel] [arch-general] Panic - no sound devices after upgrade

[Adrian Knoth]

On 07/23/11 16:21, Fons Adriaensen wrote:

Note: I suggest to narrow the CC list a bit and better move the
discussion to alsa-devel. At least, let's drop LKML and arch.

>>> Seems to have solved the problem :-) :-)
>> Good to know. I'll wait for your final confirmation and then commit it.
> 
> One problem: the gain settings have changed, now having a range of 0..64.
> How do these values map to the internal ones (0..0xffff) ? I *hope* there
> is value corresponding to EXACTLY 0x8000 (gain = 1) !!!

For the simple ALSA mixer, the driver does

   gain = ucontrol->value.integer.value[0]*UNITY_GAIN/64;

UNITY_GAIN is 32768 (0x8000), so if you select 64 on the ALSA side, it
gives you exactly what you need. Or in other words: faders to 100% in
alsamixer, that's it.

With hdspmixer or any other software that's using the full mixer, you
can still use the fine-grained 65k steps.


> BTW, why was this change made?

No idea. I reckon faberman was tired of stepping through 65k mixer
levels in alsamixer. ;) (disclaimer: I never used the old driver, so I
don't know how it was before)


Cheers