Re: [PATCH] drm/i915: Avoid spurious WARNs about the wrong pipe in the PPS code

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

On Wed, Feb 08, 2017 at 07:52:54PM +0200, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrj�l� <ville.syrjala@linux.intel.com>
> 
> Until recently vlv_steal_power_sequencer() wasn't being called for
> normal DP ports, and hence it could assert that it should only be
> called for pipe A and B (since pipe C doesn't support eDP). However
> that changed when we started to consider normal DP ports as well when
> choosing a PPS. So we will now get spurious warnings when
> vlv_steal_power_sequencer() does get called for pipe C. Avoid this by
> moving the WARN down into vlv_detach_power_sequencer() where this
> assertion should still hold.
> 
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: stable@vger.kernel.org
> Fixes: 9f2bdb006a7e ("drm/i915: Prevent PPS stealing from a normal DP port on VLV/CHV")
> References: https://bugs.freedesktop.org/show_bug.cgi?id=95287
> Signed-off-by: Ville Syrj�l� <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 0f14e97e519b..2395046e19ce 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -2905,6 +2905,9 @@ static void vlv_detach_power_sequencer(struct intel_dp *intel_dp)
>  
>  	WARN_ON(intel_dp->active_pipe != INVALID_PIPE);
>  
> +	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
> +		return;
> +

Yep, missed this:
Reviewed-by: Imre Deak <imre.deak@intel.com>

So the above is called only for eDP, checking for that too would make
things clearer imo.

>  	edp_panel_vdd_off_sync(intel_dp);
>  
>  	/*
> @@ -2932,9 +2935,6 @@ static void vlv_steal_power_sequencer(struct drm_device *dev,
>  
>  	lockdep_assert_held(&dev_priv->pps_mutex);
>  
> -	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
> -		return;
> -
>  	for_each_intel_encoder(dev, encoder) {
>  		struct intel_dp *intel_dp;
>  		enum port port;
> -- 
> 2.10.2
>