Re: [PATCH] ASoC: cs42l43: Move shutter IRQ handling into a worker thread

[Jaroslav Kysela <perex@xxxxxxxx>]

On 30. 07. 24 16:44, Mark Brown wrote:
> On Tue, Jul 30, 2024 at 04:13:33PM +0200, Jaroslav Kysela wrote:
> > On 30. 07. 24 14:33, Takashi Iwai wrote:
>
> > > OK, now it's clearer.  I think we can change snd_ctl_find_*() rather
> > > to take rwlock instead of rwsem.  It's only a quick look-up, hence
> > > rwlock can work well.
>
> > > Totally untested patch set is below.
>
> > But why the interrupt routine does not use the cached kcontrol pointer? It
> > looks like a bad driver design when you need to do such name (string based)
> > lookups from the interrupt routine.
>
> With some of these slower buses it's not immediately obvious that it's
> worth the bother of caching - the overhead of doing the lookup is
> negligable in the overall context of handling the interrupt.

I don't buy that argument. We should always try to write an optimal code. 
Every CPU tick counts.

				Jaroslav

--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.