Re: [PATCH 2/2] drm/i915: PSR: Mask LPSP hw tracking back again.

["Zanoni, Paulo R" <paulo.r.zanoni@intel.com>]

Em Qua, 2015-11-18 às 11:21 -0800, Rodrigo Vivi escreveu:
> When we introduced PSR we let LPSP masked allowing us to get PSR
> independently from the audio runtime PM. However in one of the
> attempts to get PSR enabled by default one user reported one specific
> case where he would miss screen updates if scrolling the firefox in a
> Gnome environment when i915 runtime pm was enabled. So for
> this specific case that (I could never create an i-g-t test case)
> we decided to remove the LPSP mask and let HW tracking taking care of
> this case. The mask got removed later by my
> commit 09108b90f04 ("drm/i915: PSR: Remove Low Power HW tracking
> mask.")
> 
> So we started depending on audio driver again, what is bad.
> 
> With previous commit
> "drm/i915: PSR: Let's rely more on frontbuffer tracking."
> we transfered the PSR exit responsability totally to SW frontbuffer
> tracking. So now can safelly shut off a bit the HW tracking, or
> at least this case that makes us to depend on other drivers.
> 
> v2: Update commit message since this patch by itself doesn't solve
>     the bugzilla entries.
> 
> v3: Another attempt to improve commit message.
> 
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
s/Cc/Reviewed-by/

> Tested-by: Brian Norris <briannorris@chromium.org>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_psr.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_psr.c
> b/drivers/gpu/drm/i915/intel_psr.c
> index b0e343c..b1b88d1 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -400,9 +400,14 @@ void intel_psr_enable(struct intel_dp *intel_dp)
>  				skl_psr_setup_su_vsc(intel_dp);
>  		}
>  
> -		/* Avoid continuous PSR exit by masking memup and
> hpd */
> +		/*
> +		 * Per Spec: Avoid continuous PSR exit by masking
> MEMUP and HPD.
> +		 * Also mask LPSP to avoid dependency on other
> drivers that
> +		 * might block runtime_pm besides preventing other
> hw tracking
> +		 * issues now we can rely on frontbuffer tracking.
> +		 */
>  		I915_WRITE(EDP_PSR_DEBUG_CTL(dev),
> EDP_PSR_DEBUG_MASK_MEMUP |
> -			   EDP_PSR_DEBUG_MASK_HPD);
> +			   EDP_PSR_DEBUG_MASK_HPD |
> EDP_PSR_DEBUG_MASK_LPSP);
>  
>  		/* Enable PSR on the panel */
>  		hsw_psr_enable_sink(intel_dp);
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