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

[Imre Deak <imre.deak@intel.com>]

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>

> ---
>  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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