[alsa-devel] [PATCH 1/2] ALSA: hda - Fix probing and stuttering on CMI8888 HD-audio controller

[Takashi Iwai]

At Wed, 29 Oct 2014 23:13:15 +1100,
Geoffrey McRae wrote:
> 
> On Wed, 29 Oct 2014 08:50:53 +0100
> Takashi Iwai <tiwai at suse.de> wrote:
> 
> > At Wed, 29 Oct 2014 07:21:24 +1100,
> > Geoffrey McRae wrote:
> > > 
> > > I can confirm that disable of MSI is required as even Windows 7
> > > 64bit does not enable this for Intel HDA. Out of curiosity I altered
> > > the driver to use MSI-X with the same results, interrupts are never
> > > received even though the PCI caps state that MSI is supported.
> > > 
> > > Playback is very poor and stutters if I do not allow snoop by
> > > commenting out "case AZX_DRIVER_CMEDIA:" in
> > > azx_check_snoop_available.
> > 
> > OK, so we have some conflicting results.  Possibly we need non-cached
> > pages only for CORB/RIRB but leave the stream buffers?  Could you
> > check the patch below?
> > 
> 
> The patch works fine, no errors reported, if I however disable snoop it
> continues to stutter.

OK, so the stuttering comes from the noncached pages of stream
buffers, not CORB/RIRB coherency.  I'll cook it up as a proper patch,
then.  Once when we confirm that the snoop for CORB/RIRB is really
superfluous, we can drop that hack, too.


thanks,

Takashi