Re: [PATCH v2] drm/i915: HDMI - Clear Audio Enable bit for Hot Plug unconditionally

[Takashi Iwai <tiwai@suse.de>]

At Thu, 13 Sep 2012 21:53:12 +0800,
Wang Xingchao wrote:
> 
> Hi Takashi,
> 
> 2012/9/13 Takashi Iwai <tiwai@suse.de>:
> > At Thu, 13 Sep 2012 11:19:00 +0800,
> > Wang Xingchao wrote:
> >>
> >> Clear Audio Enable bit to trigger unsolicated event to notify Audio
> >> Driver part the HDMI hot plug change. The patch fixed the bug when
> >> remove HDMI cable the bit was not cleared correctly.
> >>
> >> In intel_enable_hdmi(), if intel_hdmi->has_audio been true, the "Audio enable bit" will
> >> be set to trigger unsolicated event to notify Alsa driver the change.
> >>
> >> intel_hdmi->has_audio will be reset to false from intel_hdmi_detect() after
> >> remove the hdmi cable, here's debug log:
> >>
> >> [  187.494153] [drm:output_poll_execute], [CONNECTOR:17:HDMI-A-1] status updated from 1 to 2
> >> [  187.525349] [drm:intel_hdmi_detect], HDMI: has_audio = 0
> >>
> >> so when comes back to intel_disable_hdmi(), the "Audio enable bit" will not be cleared. And this
> >> cause the eld infomation and pin presence doesnot update accordingly in alsa driver side.
> >>
> >> This patch will also trigger unsolicated event to alsa driver to notify the hot plug event:
> >>
> >> [  187.853159] ALSA sound/pci/hda/patch_hdmi.c:772 HDMI hot plug event: Codec=3 Pin=5 Presence_Detect=0 ELD_Valid=1
> >> [  187.853268] ALSA sound/pci/hda/patch_hdmi.c:990 HDMI status: Codec=3 Pin=5 Presence_Detect=0 ELD_Valid=0
> >>
> >> Signed-off-by: Wang Xingchao <xingchao.wang@intel.com>
> >
> > We need the same fix for stable kernels, too, but unfortunately this
> > can't be applied to 3.6 or earlier.
> 
> I had another patch against 3.6 kernel, I send it out at first. This
> v2 version is based on Daniel's drm-intel-next branch.

I know.  But my point is to put a Cc line into the patch itself.

> so i will resend that seperate patch to Greg.

FYI, sending a separate stable patch would be better done once after
the original patch gets merged to Linus tree and Greg pings you due
to a cherry-pick failure.  As a rule of thumb, all stable patches
must be merged to Linus tree at first.


But, this makes me wonder why this patch can't go into 3.6.  It's a
clear bug and the fix is trivial.

Daniel, isn't it better to pick the fix (for 3.6) to drm-intel-fixes,
then merge back to drm-intel-next?


thanks,

Takashi

> 
> The patch for 3.6 kernel:
> http://lists.freedesktop.org/archives/intel-gfx/2012-September/020413.html
> 
> thanks
> --xingchao
> >
> > Greg prefers still having a Cc to stable even in such a case, and then
> > send a separate patch applicable to the existing kernels.
> >         http://lwn.net/Articles/515528/
> > So better to have a Cc to stable in the patch.
> >
> >
> > thanks,
> >
> > Takashi
> >
> >> ---
> >>  drivers/gpu/drm/i915/intel_hdmi.c |    5 +----
> >>  1 file changed, 1 insertion(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> >> index 5d02aad..229897f 100644
> >> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> >> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> >> @@ -674,10 +674,7 @@ static void intel_disable_hdmi(struct intel_encoder *encoder)
> >>       struct drm_i915_private *dev_priv = dev->dev_private;
> >>       struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(&encoder->base);
> >>       u32 temp;
> >> -     u32 enable_bits = SDVO_ENABLE;
> >> -
> >> -     if (intel_hdmi->has_audio)
> >> -             enable_bits |= SDVO_AUDIO_ENABLE;
> >> +     u32 enable_bits = SDVO_ENABLE | SDVO_AUDIO_ENABLE;
> >>
> >>       temp = I915_READ(intel_hdmi->sdvox_reg);
> >>
> >> --
> >> 1.7.9.5
> >>
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> >>
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