[alsa-devel] CPU hook snd_hda_intel

[Takashi Iwai]

On Sun, 08 Dec 2019 18:31:27 +0100,
Klaus Ethgen wrote:
> 
> Hi Takashi,
> 
> Am So den  8. Dez 2019 um  9:45 schrieb Takashi Iwai:
> > On Sat, 07 Dec 2019 21:06:43 +0100,
> > > Find attached the perf output of the relevant event handler.
> > 
> > Thanks.  So it seems wasting in the busy loop for waiting for the
> > response from the codec.
> > 
> > How about a patch below?  It's untested, might break things, but at
> > least avoiding a busy loop.
> 
> I'll give it a try. Kernel is compiling right now. It might be hard to
> see if the patch is working but I suppose that it do when I don't have
> that trouble within a week or so.
> 
> > BTW, if your machine is Coffeelake or Cannonlake, this patch wont'
> > work on the old branch because of forced polling mode.  It was removed
> > in 5.5-rc1, so please test with Linus tree at best.
> 
> I hardly have such new Architectures on that laptop. It is a lenovo x61s
> so it is from latest 2009. It has a Intel Core 2 Duo LV (Merom). :-)

OK, then could you give alsa-info.sh output, at least?
Run the script with --no-upload option and attach the output.

Basically my patch should improve a lot for Nvidia codecs, not only
about the CPU time reduction, and it'd be worth for merging to
upstream.  OTOH, it's a change at the very core part, so it needs more
testing, so it's likely for 5.6.


thanks,

Takashi