[pulseaudio-discuss] Volume control with hda_intel

[Lennart Poettering]

On Thu, 27.03.08 16:36, Steve Greenland (steveg at moregruel.net) wrote:

> 
> On 27-Mar-08, 14:19 (CDT), Lennart Poettering <lennart at poettering.net> wrote: 
> > No, this is not configurable. If the PCM slider does not work properly
> > on your sound card, then please report that to ALSA upstream. ALSA
> > (inofficially) gives the guarantee that "Master" always works for PCM
> > and "PCM" should be used as fallback. If this doesn't work on your
> > setup than this is a bug in ALSA.
> 
> After browsing the ALSA bug system, and finding that there is apparently
> lots of weirdness with the snd-hda-intel driver (or with the hardware
> itself), and lots of updates, I built and installed the 1.0.16 version
> of ALSA (not sure what's in the 2.6.24 kernel).
> 
> And JOY! The updated driver(s) create a MASTER mixer control, and it
> works in alsamixer. Curiously, the PCM control (which didn't do anything
> noticeable in the old driver) is gone, at least according to alsamixer.
> 
> And now the weird bit: pavucontrol lists the output device as
> 
>    ALSA PCM on hw:0 (ALC662 Analog) via DMA
> 
> and moving the slider does affect the volume, but it doesn't show in
> the alsamixer MASTER control, or on any other control. OTOH, the Input
> Device sliders *do* modulate the "CAPTURE" control.

PA probably refused to use your volume control due to some
reason. Please paste what "pulseaudio -vv" has to say about the volume
slider.

> >From which I conclude:
> 
> 1. Intel sound hardware is flaky

No. intel-hda just refers to a name of a standard spec. The spec is
usually not implemented by Intel. And the spec allows huge variations
in the implementations. And then most implementors add all their own
set of design bugs to their hw. 

It's not really Intel's fault here.

> 2. Alsa continues to be flaky, just like it has been for years. But
> I'm not sure it's their fault; it looks like every implentation of
> snd-hda-intel is broken in different ways.

ALSA has its issues, but in this case this is probably more the hw
manufacturers shipping faulty hw, that doesn't follow the spec or is
wired up weirdly.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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