[alsa-devel] Throughts on getting ALC892 working better (was Re: Help With Getting Line-in monitoring working)
superquad.vortex2 at gmail.com
Tue Sep 6 10:34:00 CEST 2011
2011/9/6 Kevin Atkinson <kevin at atkinson.dhs.org>:
How did you get "snd: bad kfree" in the system log ?
[ 6.272032] snd: bad kfree (called from f87381e3)
[ 6.272043] [<f85612b1>] ? snd_hidden_kfree+0x91/0xa0 [snd]
[ 6.272048] [<f87381e3>] ? snd_array_free+0x13/0x30 [snd_hda_codec]
[ 6.272052] [<f87381e3>] ? snd_array_free+0x13/0x30 [snd_hda_codec]
[ 6.272057] [<f87abfaf>] ? alc_free_kctls+0x4f/0x60 [snd_hda_codec_realtek]
[ 6.272061] [<f87affed>] ? alc_build_controls+0x44d/0x4b0
> I spent several hours going over the data sheet (ver 1.3, you can find it at
> Apparently there is no hardware master control and the master and PCM slider
> must be implemented in software.
> So, after the change you suggest below the mixer are mapped better in the
> newer drivers. But things can be still be improved. More below.
> Also to get line-in pass-through working via headphone out please unmute the
> second set of Amp-in vals of pin 0x26.
>> Node 0x26 [Audio Mixer] wcaps 0x20010b: Stereo Amp-In
>> Amp-In caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
>> Amp-In vals: [0x00 0x00] [0x80 0x80]
> ^^^^^^^^^^^ set these to 0x00
>> Connection: 2
>> 0x25 0x0b
The ALC892 provides ten DAC channels that simultaneously support 7.1
channel sound playback, plus 2 channels of independent stereo sound
output (multiple streaming) through the front panel stereo outputs.
you can create playback device 2 for the front panel headphone by adding
spec->alt_dac_nid = 0x25;
> Apparently all analog inputs are mixed together using 0x0B and then the
> output is sent to a bunch of other audio mixers, but these mixers don't
> really control the volume, they just have a separate mute for the PCM and
> analog input. That being said, it probably also makes sense to mute analog
> audio (coming from 0x0B) on all but pins 0x26 (headphone) and 0x0C (front)
> by default.
The hardest thing is how to add the controls for this alc892
The laptop has built-in 5.1, and 5.1 or 7.1 output via jacks.
internal speaker pins:
0x15 "rear" (front of laptop)
can select any output:
0x18 mic / output
0x1a line-in / output
> On an even lesser note, it would be really nice if ALSA could expose the
> full capacity of the hardware without having an unwieldy number of mixer
> controls. For example each of the 5 output mixers have a separate PCM and
> analog pass-though mute control, it would be nice to expose this. Also,
> each of the 8 analog pins can be repurposed as either input or output, some
> of them have a headphone amp, some of them have a mic boost, it would be
> nice if all this could all be exposed. However, I can see how exposing all
> this will lead to a lot of confusing mixer settings.
does any user really want to pass the stereo signal from line in to
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