On Thu, Apr 30, 2020 at 05:14:56PM +0200, Takashi Iwai wrote:
> On Wed, 29 Apr 2020 18:19:57 +0200,
> Alex Deucher wrote:
> >
> > On Wed, Apr 29, 2020 at 12:05 PM Takashi Iwai <tiwai@xxxxxxx> wrote:
> > > Well, but the code path there is the runtime PM resume of the audio
> > > device and it means that GPU must have been runtime-resumed again
> > > beforehand via the device link. So, it should have worked from the
> > > beginning but in reality not -- that is, apparently some inconsistency
> > > is found in the initial attempt of the runtime resume...
> >
> > Yeah, it should be covered, but I wonder if there is something in the
> > ELD update sequence that needs to call pm_runtime_get_sync()? The ELD
> > sequence on AMD GPUs doesn't work the same as on other vendors. The
> > GPU driver has a backdoor into the HDA device's verbs to set update
> > the audio state rather than doing it via an ELD buffer update. We
> > still update the ELD buffer for consistency. Maybe when the GPU
> > driver sets the audio state at monitor detection time that triggers an
> > interrupt or something on the HDA side which races with the CPU and
> > the power down of the GPU. That still seems unlikely though since the
> > runtime pm on the GPU side defaults to a 5 second suspend timer.
>
> I'm not sure whether it's the race between runtime suspend of GPU vs
> runtime resume of audio. My wild guess is rather that it's the timing
> GPU notifies to the audio; then the audio driver notifies to
> user-space and user-space opens the stream, which in turn invokes the
> runtime resume of GPU. But in GPU side, it's still under processing,
> so it proceeds before the GPU finishes its initialization job.
>
> Nicholas, could you try the patch below and see whether the problem
> still appears? The patch artificially delays the notification and ELD
> update for 300msec. If this works, it means the timing problem.
The bug still occurred after applying the patch.
But you were absolutely correct - it just needed to be increased to
3000ms - then the bug stopped.
Now the question is, what do we do now that we know this?
Also, are you still interested in the contents of the ELD# files? I can
dump them all into a file at some specific moment in time which you
request, if needed.
Thanks.
Regards, Nicholas
>
>
> thanks,
>
> Takashi
>
> --- a/sound/pci/hda/patch_hdmi.c
> +++ b/sound/pci/hda/patch_hdmi.c
> @@ -767,6 +767,7 @@ static void check_presence_and_report(struct hda_codec *codec, hda_nid_t nid,
> if (pin_idx < 0)
> return;
> mutex_lock(&spec->pcm_lock);
> + get_pin(spec, pin_idx)->repoll_count = 1;
> hdmi_present_sense(get_pin(spec, pin_idx), 1);
> mutex_unlock(&spec->pcm_lock);
> }
> @@ -1647,7 +1648,10 @@ static void sync_eld_via_acomp(struct hda_codec *codec,
> per_pin->dev_id, &eld->monitor_present,
> eld->eld_buffer, ELD_MAX_SIZE);
> eld->eld_valid = (eld->eld_size > 0);
> - update_eld(codec, per_pin, eld, 0);
> + if (per_pin->repoll_count)
> + schedule_delayed_work(&per_pin->work, msecs_to_jiffies(300));
> + else
> + update_eld(codec, per_pin, eld, 0);
> mutex_unlock(&per_pin->lock);
> }
>
> @@ -1669,6 +1673,11 @@ static void hdmi_repoll_eld(struct work_struct *work)
> struct hdmi_spec *spec = codec->spec;
> struct hda_jack_tbl *jack;
>
> + if (codec_has_acomp(codec)) {
> + per_pin->repoll_count = 0;
> + goto check;
> + }
> +
> jack = snd_hda_jack_tbl_get_mst(codec, per_pin->pin_nid,
> per_pin->dev_id);
> if (jack)
> @@ -1677,6 +1686,7 @@ static void hdmi_repoll_eld(struct work_struct *work)
> if (per_pin->repoll_count++ > 6)
> per_pin->repoll_count = 0;
>
> + check:
> mutex_lock(&spec->pcm_lock);
> hdmi_present_sense(per_pin, per_pin->repoll_count);
> mutex_unlock(&spec->pcm_lock);
