[pulseaudio-discuss] [alsa-devel] pulseaudio fails to start with kernel 4.11, caused by new snd_hdmi_lpe_audio module)

[Tanu Kaskinen]

On Wed, 2017-03-29 at 15:26 +0200, Takashi Iwai wrote:
> On Wed, 29 Mar 2017 15:14:19 +0200,
> Tanu Kaskinen wrote:
> > 
> > On Wed, 2017-03-29 at 15:06 +0200, Takashi Iwai wrote:
> > > On Wed, 29 Mar 2017 14:59:45 +0200,
> > > Tanu Kaskinen wrote:
> > > > 
> > > > On Wed, 2017-03-29 at 07:21 +0200, Takashi Iwai wrote:
> > > > > Does PA really need to start streaming at its invocation time?
> > > > > The crash happens when PA gets started via desktop autostart, and at
> > > > > this moment, the HDMI graphics state is possible disconnected before
> > > > > xrandr setup.  The HDMI connection state should have been informed /
> > > > > notified to PA via the jack interface, so it should be possible to
> > > > > judge beforehand.
> > > > > 
> > > > > Or it might be something wrong in the driver side regarding the jack
> > > > > state processing?
> > > > 
> > > > I had a closer look at the PA log that was posted earlier. It looks
> > > > like the device numbering is non-standard. Trying to open any of the
> > > > hdmi:1,x devices fails. hw:1 can be opened, and pulseaudio assumes that
> > > > it's an analog stereo device. Jack detection isn't going to work in
> > > > this situation, because pulseaudio doesn't know that it should be
> > > > looking at the hdmi jacks.
> > > > 
> > > > Can the driver be fixed to use the standard HDMI device numbers?
> > > 
> > > Hmm, it might be the missing hdmi PCM definition?
> > > 
> > > The latest alsa-lib git already contains the card config for HDMI LPE
> > > audio, and this might help.  (Though, I thought I still saw the same
> > > PA problem even with the card config.  Unfortunately I can't access
> > > the box with the DP audio right now, so others may help more quickly
> > > than me...)
> > > 
> > > Can anyone confirm that you have the latest alsa-lib git installed and
> > > whether the PA issue is fixed or not?
> > 
> > If the alsa-lib configuration just maps hdmi:1,0 to hw:1,0, then I
> > would expect this problem to persist. If hw:1,0 can be opened,
> > pulseaudio will think that there's an analog stereo output. If hdmi:1,0
> > works too, then pulseaudio will think that there are two separate
> > outputs, and if the hdmi jack state says that hdmi is not available,
> > pulseaudio will use what it thinks is an analog output.
> 
> Aha, that explains.
> 
> > If it's not possible to change the device numbering in the driver, this
> > will have to be worked around in pulseaudio somehow (pulseaudio
> > shouldn't try to use hw:1,0 on this hardware).
> 
> Well, it's not impossible to change in the driver side, but I hesitate
> to do so, since it's not right, IMO.
> 
> In general, the PCM device#0 isn't always for an analog output,
> although it's de facto standard, as most boards have both analog and
> HDMI/DP.  For HD-audio, we even kept the constant PCM dev# even if no
> analog output is present; but it's just to make the configuration
> easier, and it doesn't mean that PCM dev#0 is for the analog I/O.

I agree, it's not good to assume that hw:x,0 is always analog stereo
output. Pulseaudio should fall back to hw: only if nothing else works.

The jack name problem is easily solved in pulseaudio, but there's one
more problem related to the device numbers: pulseaudio needs to know
which ELD element corresponds to which PCM device. Currently the
mapping is hardcoded: hdmi:x,0 is expected to always correspond to the
ELD element of device 3. Is there any way pulseaudio could query the
mapping instead of hardcoding it?

-- 
Tanu

https://www.patreon.com/tanuk