At Mon, 07 Oct 2013 13:31:17 +0300,
Anssi Hannula wrote:
>
> Takashi Iwai kirjoitti 2013-10-07 10:48:
> > At Wed, 2 Oct 2013 21:13:32 +0300,
> > Anssi Hannula wrote:
> >
> > Currently hdmi_setup_audio_infoframe() reprograms the HDA channel
> > mapping only when the infoframe is not up-to-date or the non-PCM flag
> > has changed.
> >
> > However, when just the channel map has been changed, the infoframe may
> > still be up-to-date and non-PCM flag may not have changed, so the new
> > channel map is not actually programmed into the HDA codec.
> >
> > Notably, this failing case is also always triggered when the device is
> > already in a prepared state and a new channel map is configured while
> > changing only the channel positions (for example, plain
> > "speaker-test -c2 -m FR,FL").
> >
> > Fix that by keeping track of the last programmed channel map and making
> > hdmi_setup_audio_infoframe() always update the hardware mapping if the
> > channel map has changed.
> >
> > Hmm, maybe it's easier (and safer) to remove the check and always call
> > hdmi_setup_channel_mapping()? Of course, the drawback is the
> > unnecessary verbs, but it's not too much.
>
> Easier, yes. I don't really have that good of an idea how big of a delay
> do 8 write verbs cause, so I'll rely on your judgment :)
>
> I guess I could replace the writes with read-and-write-if-differs cycles
> when I add the set_slot ops for ATI/AMD, since it seems to be used for
> other similar cases (like channel count)?
Well, this would result in more cost, as read requires a sync.
If any, we can use the cached write/update. But this assumes that the
hardware never clears the value by some operation internally.
> > Signed-off-by: Anssi Hannula <anssi.hannula@xxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > ---
> >
> > BTW, is there some mechanism preventing hdmi_chmap_ctl_put() to be
> > called
> > at the same time with generic_hdmi_playback_pcm_prepare() that I didn't
> > see with a quick look?
> > Both of them call hdmi_setup_audio_infoframe() which is not
> > thread-safe.
> >
> > Yeah, we need to introduce a mutex there.
>
> I guess hdmi_present_sense() is the same, as it can also call
> hdmi_setup_audio_infoframe()?
Hm, looking at the code, we have already pin_eld->lock in
hdmi_present_sense(). This can be used in other places, too.
(And pin_eld->monitor_present change at the beginning of
hdmi_present_sense() should be protected in the mutex, too...)
> BTW, shouldn't hdmi_present_sense() call hdmi_setup_audio_infoframe()
> always
> when eld_changed is true? hdmi_setup_audio_infoframe() does not do its
> stuff if !monitor_present, so if one starts playback before plugging in,
> the channel mappings etc will never be set even when plug-in happens
> (from what I can see, that is - did not test yet).
Well, there is such a call but currently specific to Haswell because
it hasn't been tested for others. Maybe we can simply get rid of
is_haswell() check there.
Takashi
>
>
> > thanks,
> >
> > Takashi
> >
> > sound/pci/hda/patch_hdmi.c | 14 +++++++++++---
> > 1 file changed, 11 insertions(+), 3 deletions(-)
> >
> > diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> > index 7ea0245..09f38a1 100644
> > --- a/sound/pci/hda/patch_hdmi.c
> > +++ b/sound/pci/hda/patch_hdmi.c
> > @@ -74,6 +74,8 @@ struct hdmi_spec_per_pin {
> > bool non_pcm;
> > bool chmap_set; /* channel-map override by ALSA API? */
> > unsigned char chmap[8]; /* ALSA API channel-map */
> > + bool last_chmap_set; /* channel-map override programmed? */
> > + unsigned char last_chmap[8]; /* last programmed channel-map */
> > char pcm_name[8]; /* filled in build_pcm callbacks */
> > };
> >
> > @@ -955,15 +957,21 @@ static void hdmi_setup_audio_infoframe(struct
> > hda_codec *codec,
> > ai.bytes, sizeof(ai));
> > hdmi_start_infoframe_trans(codec, pin_nid);
> > } else {
> > - /* For non-pcm audio switch, setup new channel mapping
> > - * accordingly */
> > - if (per_pin->non_pcm != non_pcm)
> > + /* For non-pcm audio switch or channel-map switch,
> > + * setup new channel mapping accordingly */
> > + if (per_pin->non_pcm != non_pcm
> > + || per_pin->chmap_set != per_pin->last_chmap_set
> > + || (per_pin->chmap_set && memcmp(per_pin->chmap,
> > per_pin->last_chmap,
> > + ARRAY_SIZE(per_pin->chmap)) != 0))
> > hdmi_setup_channel_mapping(codec, pin_nid, non_pcm, ca,
> > channels, per_pin->chmap,
> > per_pin->chmap_set);
> > }
> >
> > per_pin->non_pcm = non_pcm;
> > + per_pin->last_chmap_set = per_pin->chmap_set;
> > + if (per_pin->chmap_set)
> > + memcpy(per_pin->last_chmap, per_pin->chmap,
> > ARRAY_SIZE(per_pin->chmap));
> > }
> >
> >
> > --
> > 1.8.1.5
> >
>
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