[Intel-gfx] snd-hda-intel runtime PM fail after module reload

[Ville Syrjälä]

On Thu, Feb 25, 2016 at 09:28:59PM +0100, Takashi Iwai wrote:
> On Thu, 25 Feb 2016 20:19:08 +0100,
> Ville Syrjälä wrote:
> > 
> > Hi,
> > 
> > My investigation into some sporadic i915 runtime PM failures seem to
> > point the finger at snd-hda-intel.
> > 
> > I just tried to play around unloding and reloading snd-hda-intel and
> > sometimes I get snd-hda-intel loaded with runtime PM supposedly enabled,
> > but actually the device won't runtime suspend. At which point frobbing
> > with power/control is enough to kick it back into submission.
> 
> Which platform are you testing?  If it's SKL, BSW or later, multiple
> codecs are on a single HD-audio bus.  In general, you have to adjust
> the runtime PM of all these codecs in addition to the runtime PM of
> the controller.  Some of them are immediately runtime PM enabled but
> some of them aren't, left the default as is.

This was on a HSW.

I also have CONFIG_SND_HDA_POWER_SAVE_DEFAULT=1 which I presume should
enable codec power saving by deafault?

> It might be that your desktop environment adjusts the runtime PM of
> HD-audio stuff, often depending on the power state.  But when you
> reload, this adjustment is also lost, so you'd have to adjust
> manually.

There's no desktop environment. Well, unless you count systemd as such.
As you can see from the log I included at least the pci device power/control
file stayed at 'auto' the whole time until I flipped it to 'on' and then
back to 'auto' to fix the problem.

Also the problem didn't happen on every reload AFAICS, so there's
something rather non-deterministic happening.

-- 
Ville Syrjälä
Intel OTC