drm/i915/psr: Implement Display WA #1136

Implement Display WA #1136 for Pre-ICL.

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>
Link: https://patchwork.freedesktop.org/patch/msgid/20230329150703.432072-7-jouni.hogander@intel.com

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);
@@ -2006,6 +2009,10 @@ 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);
 		else if (psr->enabled && !crtc_state->wm_level_disabled)

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;