Re: [Intel-gfx] [PATCH v6 6/6] drm/i915/psr: Implement Display WA #1136

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Mar 29, 2023 at 12:45:32PM +0300, Jouni Högander wrote:
> Implement Display WA #1136 for SKL/BXT.

Pre-ICL is more accurate now.

Maybe also mention here that the chicken bit approach
might work for KBL+ but implementing that is left
out for the time being.

> 
> Bspec: 21664
> 
> v2: Handle disable psr in pre/post plane hooks
> 
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_psr.c     | 7 +++++++
>  drivers/gpu/drm/i915/display/skl_watermark.c | 5 -----
>  2 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index f86d9f83429f..52f73c65d365 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -1968,11 +1968,14 @@ void intel_psr_pre_plane_update(struct intel_atomic_state *state,
>  		 * - PSR disabled in new state
>  		 * - All planes will go inactive
>  		 * - Changing between PSR versions
> +		 * - Display WA #1136: skl, bxt
>  		 */
>  		needs_to_disable |= intel_crtc_needs_modeset(new_crtc_state);
>  		needs_to_disable |= !new_crtc_state->has_psr;
>  		needs_to_disable |= !new_crtc_state->active_planes;
>  		needs_to_disable |= new_crtc_state->has_psr2 != psr->psr2_enabled;
> +		needs_to_disable |= DISPLAY_VER(i915) < 11 &&
> +			new_crtc_state->wm_level_disabled;
>  
>  		if (psr->enabled && needs_to_disable)
>  			intel_psr_disable_locked(intel_dp);
> @@ -2007,6 +2010,10 @@ static void _intel_psr_post_plane_update(const struct intel_atomic_state *state,
>  		keep_disabled |= psr->sink_not_reliable;
>  		keep_disabled |= !crtc_state->active_planes;
>  
> +		/* Display WA #1136: skl, bxt */
> +		keep_disabled |= DISPLAY_VER(dev_priv) < 11 &&
> +			crtc_state->wm_level_disabled;
> +
>  		if (!psr->enabled && !keep_disabled)
>  			intel_psr_enable_locked(intel_dp, crtc_state);
>  
> diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c b/drivers/gpu/drm/i915/display/skl_watermark.c
> index 7e2e76afbf2a..5296a20d62d3 100644
> --- a/drivers/gpu/drm/i915/display/skl_watermark.c
> +++ b/drivers/gpu/drm/i915/display/skl_watermark.c
> @@ -2281,11 +2281,6 @@ static int skl_wm_check_vblank(struct intel_crtc_state *crtc_state)
>  	 */
>  	crtc_state->wm_level_disabled = level < i915->display.wm.num_levels - 1;
>  
> -	/*
> -	 * FIXME also related to skl+ w/a 1136 (also unimplemented as of
> -	 * now) perhaps?
> -	 */
> -
>  	for (level++; level < i915->display.wm.num_levels; level++) {
>  		enum plane_id plane_id;
>  
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel