[alsa-devel] [PATCH] Acer Aspire 8930G support

[Takashi Iwai]

At Tue, 02 Jun 2009 08:58:03 +0200,
Hector Martin wrote:
> 
> Getting this one to work has annoyed me to no end.
> 
> Short story: this laptop has 5.1 built-in speakers which you *really*
> want to use (the not-so-"sub" woofer is what makes the audio above
> average for a laptop), so 6-channel support is important (plus a decent
> asound.conf to upmix stereo). It also has the 3 typical jacks that ought
> to have a selectable mode. And it's based on ALC889, which sucks.
> 
> Rationale/explanations:
> 
> The const_channel_count stuff was added because, for a laptop like this,
> you always have 6 channels available (internal speakers) but still need
> to set the mode for the 3 external jacks. Therefore, the device always
> needs to be in 6-channel mode but there still needs to be a mixer
> control for the jack mode. You could use line/mic-in at the same time as
> the 6 internal speakers, for example. You might be tempted to make it
> even smarter by dynamically switching the max channel count when
> headphones are plugged in (therefore muting the internal speakers and
> reducing the physical channel count to the jack channel mode), but as a
> user I consider this to be harmful because I want the audio to blow up
> to 6 channels / upmixed as soon as I unplug the headphones, and having
> opened the device while in 2-channel mode would prevent this from
> working (and always making 6-channel mode available doesn't do any harm).

This change looks OK.


> The hardware needs EAPD turned on and the DACs routed to the internal
> speaker pins, so the patch adds those verbs.
> 
> The ALC889 CLFE and subsequent (side/aux, here unused) DACs do NOT work
> by default, at least here. I wasted much time trying to talk to
> Realtek/pshou about this, but they just kept sending me useless updates
> to patch_realtek.c that did nothing relevant. In the end I gave up and
> brute forced the issue by trying to flip every bit in the proprietary
> coefficient registers, and eventually found the two magic registers that
> need to be cleared to enable all DACs. I have only heard Acer users
> complain, but that might be because ALC889 is pretty new and using 5.1
> (and noticing the missing center/lfe channels) might not be that common.
> If this is a generalized issue with all ALC889 systems then those verbs
> should probably be moved to a common verb array.

Oh, it's a good finding.

> The internal mic is untested and probably doesn't work.
> 
> These settings will probably work for other Acer Gemstone laptops with
> the same 5.1 speaker config. When identified, those should be added to
> the PCI subsystem ID list.

The changes you made are fine, but could you reformat the patch as
checkpatch.pl-clean and repost?


thanks,

Takashi