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

[Takashi Iwai]

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 at intel.com>

We need the same fix for stable kernels, too, but unfortunately this
can't be applied to 3.6 or earlier.

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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