Re: [PATCH] drm/i915: intel_audio clear eld buf when disconnecting monitor

[Takashi Iwai <tiwai@suse.de>]

On Mon, 21 Mar 2016 16:12:05 +0100,
Takashi Iwai wrote:
> 
> On Mon, 21 Mar 2016 16:00:21 +0100,
> Takashi Iwai wrote:
> > 
> > On Mon, 21 Mar 2016 15:17:37 +0100,
> > Yang, Libin wrote:
> > > 
> > > 
> > > > -----Original Message-----
> > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > Sent: Monday, March 21, 2016 6:45 PM
> > > > To: libin.yang@linux.intel.com
> > > > Cc: intel-gfx@lists.freedesktop.org; conselvan2@gmail.com;
> > > > jani.nikula@linux.intel.com; ville.syrjala@linux.intel.com; Vetter, Daniel;
> > > > tiwai@suse.de; Yang, Libin
> > > > Subject: Re: [PATCH] drm/i915: intel_audio clear eld buf when
> > > > disconnecting monitor
> > > > 
> > > > On Mon, 21 Mar 2016 06:03:29 +0100,
> > > > libin.yang@linux.intel.com wrote:
> > > > >
> > > > > From: Libin Yang <libin.yang@linux.intel.com>
> > > > >
> > > > > When disconnecting monitor, dev_priv->dig_port_map[port]
> > > > > will be set NULL, which causes eld will not be updated in
> > > > > i915_audio_component_get_eld().
> > > > >
> > > > > This patch clears the eld buf when dev_priv->dig_port_map[port]
> > > > > is NULL.
> > > > >
> > > > > Signed-off-by: Libin Yang <libin.yang@linux.intel.com>
> > > > 
> > > > While this isn't certainly bad, I don't think it's mandatory.  The
> > > > function returns zero, i.e. no data is copied.  So the caller
> > > > shouldn't expect that the buffer is cleared in this case.
> > > 
> > > Without the patch, we find when unplug the monitor, the eld info
> > > will not be updated. The means the eld info in the procfs still remains
> > > the old info after the monitor is disconnected.
> > 
> > Well, it's not about zero-clear but rather because the function
> > returns an error (-EINVAL), and the caller takes it too seriously.
> > Upon receiving an error code, the HDA driver doesn't read ELD at all,
> > so it won't help even if you do zero-clear there.
> > 
> > The alternative fix patch is below.
> 
> ... or we can fix it in HDA side like below, too.

This patch won't be applied cleanly on the upstream tree as I wrote it
on the my working tree, sorry.  Below is the revised one that is
applicable to upstream tree.


Takashi

-- 8< --
From: Takashi Iwai <tiwai@suse.de>
Subject: [PATCH v2] ALSA: hda - Fix missing ELD update at unplugging

i915 get_eld ops may return an error when no encoder is connected, and
currently we regard the error as fatal and skip the whole ELD
handling.  This ended up with the missing ELD update at unplugging.

This patch fixes the issue by treating the error as the unplugged
state, instead of skipping the rest.

Reported-by: Libin Yang <libin.yang@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.5
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/pci/hda/patch_hdmi.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 7ae614d27954..d9a557ea7a5b 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -1484,11 +1484,10 @@ static void sync_eld_via_acomp(struct hda_codec *codec,
 	int size;
 
 	mutex_lock(&per_pin->lock);
+	*eld->monitor_present = false;
 	size = snd_hdac_acomp_get_eld(&codec->bus->core, per_pin->pin_nid,
 				      &eld->monitor_present, eld->eld_buffer,
 				      ELD_MAX_SIZE);
-	if (size < 0)
-		goto unlock;
 	if (size > 0) {
 		size = min(size, ELD_MAX_SIZE);
 		if (snd_hdmi_parse_eld(codec, &eld->info,
-- 
2.7.4

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx