[alsa-devel] [PATCH] ASoC: Fix dapm_is_shared_kcontrol so everything isn't shared

[Jarkko Nikula]

Hi Stephen

On Wed, 25 May 2011 10:01:55 +0300
Jarkko Nikula <jhnikula at gmail.com> wrote:

> On Tue, 24 May 2011 17:12:01 -0600
> Stephen Warren <swarren at nvidia.com> wrote:
> 
> > Commit af46800 ("ASoC: Implement mux control sharing") introduced
> > function dapm_is_shared_kcontrol.
> > 
> > When this function returns true, the naming of DAPM controls is derived
> > from the kcontrol_new. Otherwise, the name comes from the widget (and
> > possibly a widget's naming prefix).
> > 
> > A bug in the implementation of dapm_is_shared_kcontrol made it return 1
> > in all cases. Hence, that commit caused a change in control naming for
> > all controls instead of just shared controls.
> > 
> > Specifically, a control is always considered shared because it is always
> > compared against itself. Solve this by never comparing against the widget
> > containing the control being created.
> > 
> > I tested that with the Tegra WM8903 driver:
> > * Shared is now mostly 0 as expected, and sometimes 1.
> > * The expected controls are still generated after this change.
> > 
> > Howwever, I don't have any systems that have a widget/control naming
> > prefix, so I can't test that aspect.
> > 
> > Reported-by: Liam Girdwood <lrg at ti.com>
> > Root-caused-by: Jarkko Nikula <jhnikula at gmail.com>

I would rather see here Reported-by/Tested-by as I don't feel that I
broke here something :-)

> Hmm.. it seems this test is not enough with tlv320aic3x.c. It still
> classifies a lot of kcontrols to be shared. Will keep hunting.
> 
I managed to find why this didn't work with tlv320aic3x.c on rx51.c.

This triggered out that "[Left | Right] Line1[L | R]" Muxes in
tlv320aic3x were pointing to same mux controls which is wrong since
there are separate registers for them. I prepare a fix for this
hopefully tomorrow.

Then we must skip test for widgets that are in different dapm context,
i.e. we don't want to share mux controls if they are in different device
instance. Does it work for you if you add the dapm test below to your
patch?

@@ -334,6 +335,8 @@ static int dapm_is_shared_kcontrol(struct
snd_soc_dapm_context *dapm, *kcontrol = NULL;
 
 	list_for_each_entry(w, &dapm->card->widgets, list) {
+		if (w == kcontrolw || w->dapm != kcontrolw->dapm)
+			continue;

-- 
Jarkko