Re: [PATCH] drm/i915: Cancel vdd off work before suspend

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 25 Nov 2014, Imre Deak <imre.deak@intel.com> wrote:
> On Tue, 2014-11-25 at 15:43 +0200, ville.syrjala@linux.intel.com wrote:
>> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> 
>> Currently we just make sure vdd is off before suspending, but we don't
>> cancel the vdd off work. The work wil not touch vdd if
>> want_panel_vdd==false so in theory this is fine.
>> 
>> In the past that was perfectly fine since the vdd off work didn't do
>> anything when want_panel_vdd==false, so even if the work would have been
>> run during system resume before i915 has resumed, nothing would happen.
>> 
>> However since pps_lock() will now grab the power domain references before
>> it can check want_panel_vdd, we may end up toggling the power wells on/off
>> already before the driver has resumed. That is not really acceptable, so
>> cancel the vdd off work when suspending the encoder.
>> 
>> The problem appeared when pps_lock() was introduced in:
>>  commit 773538e86081d146e0020435d614f4b96996c1f9
>>  Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>  Date:   Thu Sep 4 14:54:56 2014 +0300
>> 
>>     drm/i915: Reset power sequencer pipe tracking when disp2d is off
>> 
>> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Reviewed-by: Imre Deak <imre.deak@intel.com>

Pushed to drm-intel-fixes, thanks for the patch and review.

BR,
Jani.

>
>> ---
>>  drivers/gpu/drm/i915/intel_dp.c | 1 +
>>  1 file changed, 1 insertion(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index 46731da..d2529ec 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -4335,6 +4335,7 @@ static void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
>>  	 * vdd might still be enabled do to the delayed vdd off.
>>  	 * Make sure vdd is actually turned off here.
>>  	 */
>> +	cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
>>  	pps_lock(intel_dp);
>>  	edp_panel_vdd_off_sync(intel_dp);
>>  	pps_unlock(intel_dp);
>
>
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-- 
Jani Nikula, Intel Open Source Technology Center
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