[alsa-devel] [PATCH 3/3] ALSA: hda - hdmi: Notify userspace when ELD control changes

[Takashi Iwai]

At Mon, 18 Feb 2013 15:46:04 +0100,
David Henningsson wrote:
> 
> On 02/18/2013 03:41 PM, Takashi Iwai wrote:
> > At Mon, 18 Feb 2013 14:11:13 +0100,
> > David Henningsson wrote:
> >>
> >> Since ELD sometimes becomes available a while after we have detected
> >> presence, we need to be able to listen for changes on the ELD control.
> >>
> >> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
> >> ---
> >>   sound/pci/hda/patch_hdmi.c |   10 ++++++++++
> >>   1 file changed, 10 insertions(+)
> >>
> >> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> >> index 9236cdb..d3b1a93 100644
> >> --- a/sound/pci/hda/patch_hdmi.c
> >> +++ b/sound/pci/hda/patch_hdmi.c
> >> @@ -74,6 +74,7 @@ struct hdmi_spec_per_pin {
> >>
> >>   	struct hda_codec *codec;
> >>   	struct hdmi_eld sink_eld;
> >> +	struct snd_kcontrol *eld_ctl;
> >>   	struct delayed_work work;
> >>   	int repoll_count;
> >>   	bool non_pcm;
> >> @@ -406,6 +407,7 @@ static int hdmi_create_eld_ctl(struct hda_codec *codec, int pin_idx,
> >>   	if (err < 0)
> >>   		return err;
> >>
> >> +	spec->pins[pin_idx].eld_ctl = kctl;
> >>   	return 0;
> >>   }
> >>
> >> @@ -1175,6 +1177,7 @@ static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
> >>   	 */
> >>   	int present = snd_hda_pin_sense(codec, pin_nid);
> >>   	bool eld_valid = false;
> >> +	bool old_eld_valid = eld->eld_valid;
> >>
> >>   	memset(eld, 0, offsetof(struct hdmi_eld, eld_buffer));
> >>
> >> @@ -1196,6 +1199,13 @@ static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
> >>   					   msecs_to_jiffies(300));
> >>   		}
> >>   	}
> >> +
> >> +	if (eld->eld_valid != old_eld_valid && per_pin->eld_ctl) {
> >> +		snd_ctl_notify(codec->bus->card,
> >> +			       SNDRV_CTL_EVENT_MASK_VALUE | SNDRV_CTL_EVENT_MASK_INFO,
> >> +			       &per_pin->eld_ctl->id);
> >> +	}
> >
> > This notification should be skipped when the pin sensing is requeued.
> 
> I don't understand this comment. Are you referring to repolling the ELD? 

Yes.

> eld->eld_valid is never set to TRUE when repoll happens.

But old_eld_valid might be TRUE, and you cleared eld->eld_valid to
FALSE now before the actual probe result.  Thus the check above passes
and sends a notification although the actual probe isn't done.


Takashi