I tried model=6stck-dig, I'm sorry (it's a typo in the hda_codec.txt
which comes with the kernel)

I've fixed it and will get it upstream in another email, thanks.

with 6stack-dig, the module accept the option but I get (it seems) the
same controls as bios-tried, so not any master control (maybe there is
no such control on this board, I don't know, but I think it should be)
I've tried 6stack-dig, 3stack-dig, and arima but it's 6stack-dig (or
bios) that fit the best.

I'll add that to the code for now.

Should I try with model that aren't ALC882 ? (I've tried one, but it's
not accepted, I don't know if I should try all of them)

No, because it wouldn't work. When snd-hda-intel loads, it looks at the codecs on the bus (there can be 16), and determines the vendor and model. It then looks at the tables to see if that vendor/model is listed (each of the patch_*.c files has their own table at the end of the file). If a correct entry is found, the table tells the driver which patch to use, and each patch has different configuration definitions.
The patch looks at it's own table to match your pci subsystem ID so that it can load the correct settings for your motherboard. If your subsystem ID isn't listed, then the driver will revert to "auto" mode.

Hope that explanation helps.

As to a Master Volume, I can look into adding it if you'd be willing to give it a test run. I'll need one piece of output from your system, though. Type "cat /proc/asound/version /proc/asound/card0/codec* >Asus-p5W-codec.out" and send it to me.

I won't be able to get to it until next week at the earliest, but maybe we can get it working.

--
Tobin Davis <tdavis@dsl-only.net>