drm/i915/dsb: Use chained DSBs for LUT programming

In order to better handle the necessary DSB DEwake tricks let's
switch over to using a chained DSB for the actual LUT programming.
The CPU will start 'dsb_color_commit', which in turn will start the
chained 'dsb_color_vblank'.

Signed-off-by: Ville Syrjälä <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Reviewed-by: Animesh Manna <[email protected]>

Author: vsyrjala

drivers/gpu/drm/i915/display/intel_atomic.c

@@ -277,6 +277,7 @@ intel_crtc_duplicate_state(struct drm_crtc *crtc)
 	crtc_state->fb_bits = 0;
 	crtc_state->update_planes = 0;
 	crtc_state->dsb_color_vblank = NULL;
+	crtc_state->dsb_color_commit = NULL;
 
 	return &crtc_state->uapi;
 }
@@ -311,6 +312,7 @@ intel_crtc_destroy_state(struct drm_crtc *crtc,
 	struct intel_crtc_state *crtc_state = to_intel_crtc_state(state);
 
 	drm_WARN_ON(crtc->dev, crtc_state->dsb_color_vblank);
+	drm_WARN_ON(crtc->dev, crtc_state->dsb_color_commit);
 
 	__drm_atomic_helper_crtc_destroy_state(&crtc_state->uapi);
 	intel_crtc_free_hw_state(crtc_state);

drivers/gpu/drm/i915/display/intel_color.c

@@ -1890,8 +1890,8 @@ void intel_color_commit_arm(const struct intel_crtc_state *crtc_state)
 
 	i915->display.funcs.color->color_commit_arm(crtc_state);
 
-	if (crtc_state->dsb_color_vblank)
-		intel_dsb_commit(crtc_state->dsb_color_vblank, true);
+	if (crtc_state->dsb_color_commit)
+		intel_dsb_commit(crtc_state->dsb_color_commit, false);
 }
 
 void intel_color_post_update(const struct intel_crtc_state *crtc_state)
@@ -1919,26 +1919,44 @@ void intel_color_prepare_commit(struct intel_atomic_state *state,
 	if (!crtc_state->pre_csc_lut && !crtc_state->post_csc_lut)
 		return;
 
-	crtc_state->dsb_color_vblank = intel_dsb_prepare(state, crtc, INTEL_DSB_0, 1024);
+	crtc_state->dsb_color_vblank = intel_dsb_prepare(state, crtc, INTEL_DSB_1, 1024);
 	if (!crtc_state->dsb_color_vblank)
 		return;
 
 	i915->display.funcs.color->load_luts(crtc_state);
 
 	intel_dsb_finish(crtc_state->dsb_color_vblank);
+
+	crtc_state->dsb_color_commit = intel_dsb_prepare(state, crtc, INTEL_DSB_0, 16);
+	if (!crtc_state->dsb_color_commit) {
+		intel_dsb_cleanup(crtc_state->dsb_color_vblank);
+		crtc_state->dsb_color_vblank = NULL;
+		return;
+	}
+
+	intel_dsb_chain(state, crtc_state->dsb_color_commit,
+			crtc_state->dsb_color_vblank, true);
+
+	intel_dsb_finish(crtc_state->dsb_color_commit);
 }
 
 void intel_color_cleanup_commit(struct intel_crtc_state *crtc_state)
 {
-	if (!crtc_state->dsb_color_vblank)
-		return;
+	if (crtc_state->dsb_color_commit) {
+		intel_dsb_cleanup(crtc_state->dsb_color_commit);
+		crtc_state->dsb_color_commit = NULL;
+	}
 
-	intel_dsb_cleanup(crtc_state->dsb_color_vblank);
-	crtc_state->dsb_color_vblank = NULL;
+	if (crtc_state->dsb_color_vblank) {
+		intel_dsb_cleanup(crtc_state->dsb_color_vblank);
+		crtc_state->dsb_color_vblank = NULL;
+	}
 }
 
 void intel_color_wait_commit(const struct intel_crtc_state *crtc_state)
 {
+	if (crtc_state->dsb_color_commit)
+		intel_dsb_wait(crtc_state->dsb_color_commit);
 	if (crtc_state->dsb_color_vblank)
 		intel_dsb_wait(crtc_state->dsb_color_vblank);
 }

drivers/gpu/drm/i915/display/intel_display.c

@@ -7514,6 +7514,7 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 		 * FIXME get rid of this funny new->old swapping
 		 */
 		old_crtc_state->dsb_color_vblank = fetch_and_zero(&new_crtc_state->dsb_color_vblank);
+		old_crtc_state->dsb_color_commit = fetch_and_zero(&new_crtc_state->dsb_color_commit);
 	}
 
 	/* Underruns don't always raise interrupts, so check manually */

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1397,7 +1397,7 @@ struct intel_crtc_state {
 	enum transcoder mst_master_transcoder;
 
 	/* For DSB based color LUT updates */
-	struct intel_dsb *dsb_color_vblank;
+	struct intel_dsb *dsb_color_vblank, *dsb_color_commit;
 
 	u32 psr2_man_track_ctl;