[Intel-gfx] [PATCH 6/8] drm/i915/psr: Use WA to force HW tracking to exit PSR2

[Rodrigo Vivi]

On Thu, Sep 20, 2018 at 01:43:25PM -0700, José Roberto de Souza wrote:
> This WA also works fine for PSR2, triggering a selective update when
> possible.

Oh! really?! It didn't work when I chacked on my CNL,
but we probably had other bugs back there...

Thanks for finding this


Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>



> 
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_psr.c | 24 ++++++++++--------------
>  1 file changed, 10 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 84b512426514..cf9d6e965697 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -1026,20 +1026,16 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
>  
>  	/* By definition flush = invalidate + flush */
>  	if (frontbuffer_bits) {
> -		if (dev_priv->psr.psr2_enabled) {
> -			intel_psr_exit(dev_priv);
> -		} else {
> -			/*
> -			 * Display WA #0884: all
> -			 * This documented WA for bxt can be safely applied
> -			 * broadly so we can force HW tracking to exit PSR
> -			 * instead of disabling and re-enabling.
> -			 * Workaround tells us to write 0 to CUR_SURFLIVE_A,
> -			 * but it makes more sense write to the current active
> -			 * pipe.
> -			 */
> -			I915_WRITE(CURSURFLIVE(pipe), 0);
> -		}
> +		/*
> +		 * Display WA #0884: all
> +		 * This documented WA for bxt can be safely applied
> +		 * broadly so we can force HW tracking to exit PSR
> +		 * instead of disabling and re-enabling.
> +		 * Workaround tells us to write 0 to CUR_SURFLIVE_A,
> +		 * but it makes more sense write to the current active
> +		 * pipe.
> +		 */
> +		I915_WRITE(CURSURFLIVE(pipe), 0);
>  	}
>  
>  	if (!dev_priv->psr.active && !dev_priv->psr.busy_frontbuffer_bits)
> -- 
> 2.19.0
>