drm/vc4: hvs: Defer updating the enable_bg_fill until vblank

The register to enable/disable background fill was being set from atomic flush, however that will be applied immediately and can be a while before the vblank. If it was required for the current frame but not for the next one, that can result in corruption for part of the current frame. Store the state in vc4_hvs, and update it on vblank. Signed-off-by: Dave Stevenson <[email protected]>
raspberrypi · Nov 19, 2024 · 57b528e · 57b528e
1 parent dbf1279
commit 57b528e
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Showing 2 changed files with 12 additions and 8 deletions.
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -365,6 +365,8 @@ struct vc4_hvs {
 		unsigned int enabled: 1;
 	} eof_irq[HVS_NUM_CHANNELS];
 
+	bool bg_fill[HVS_NUM_CHANNELS];
+
 	unsigned long max_core_rate;
 
 	/* Memory manager for CRTCs to allocate space in the display

diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -1509,14 +1509,7 @@ void vc4_hvs_atomic_flush(struct drm_crtc *crtc,
 		/* This sets a black background color fill, as is the case
 		 * with other DRM drivers.
 		 */
-		if (enable_bg_fill)
-			HVS_WRITE(SCALER6_DISPX_CTRL1(channel),
-				  HVS_READ(SCALER6_DISPX_CTRL1(channel)) |
-				  SCALER6(DISPX_CTRL1_BGENB));
-		else
-			HVS_WRITE(SCALER6_DISPX_CTRL1(channel),
-				  HVS_READ(SCALER6_DISPX_CTRL1(channel)) &
-				  ~SCALER6(DISPX_CTRL1_BGENB));
+		hvs->bg_fill[channel] = enable_bg_fill;
 	} else {
 		/* we can actually run with a lower core clock when background
 		 * fill is enabled on VC4_GEN_5 so leave it enabled always.
@@ -1700,6 +1693,15 @@ static irqreturn_t vc6_hvs_eof_irq_handler(int irq, void *data)
 		if (hvs->eof_irq[i].desc != irq)
 			continue;
 
+		if (hvs->bg_fill[i])
+			HVS_WRITE(SCALER6_DISPX_CTRL1(i),
+				  HVS_READ(SCALER6_DISPX_CTRL1(i)) |
+				  SCALER6(DISPX_CTRL1_BGENB));
+		else
+			HVS_WRITE(SCALER6_DISPX_CTRL1(i),
+				  HVS_READ(SCALER6_DISPX_CTRL1(i)) &
+				  ~SCALER6(DISPX_CTRL1_BGENB));
+
 		vc4_hvs_schedule_dlist_sweep(hvs, i);
 		return IRQ_HANDLED;
 	}