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

[Rodrigo Vivi]

Hi Daniel

Would you please consider merging patches 2,3 and 4 from this series
that are ready to get merged?
They don't depend on patch 1 that is under review yet.

Thanks,

On Wed, Nov 18, 2015 at 1:49 PM, Rodrigo Vivi <rodrigo.vivi at intel.com> wrote:
> 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 at intel.com>
> Tested-by: Brian Norris <briannorris at chromium.org>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at 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);
> --
> 2.4.3
>
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-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br