1 files changed, 23 insertions, 7 deletions

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 17741843cf51..90dacab67be5 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -226,9 +226,6 @@ static void rcar_du_crtc_set_display_timing(struct rcar_du_crtc *rcrtc)
 		 * system clock, and have no internal clock divider.
 		 */
 
-		if (WARN_ON(!rcrtc->extclock))
-			return;
-
 		/*
 		 * The H3 ES1.x exhibits dot clock duty cycle stability issues.
 		 * We can work around them by configuring the DPLL to twice the
@@ -701,7 +698,7 @@ static void rcar_du_crtc_atomic_begin(struct drm_crtc *crtc,
 	 * CRTC will be put later in .atomic_disable().
 	 *
 	 * If a mode set is not in progress the CRTC is enabled, and the
-	 * following get call will be a no-op. There is thus no need to belance
+	 * following get call will be a no-op. There is thus no need to balance
 	 * it in .atomic_flush() either.
 	 */
 	rcar_du_crtc_get(rcrtc);
@@ -738,10 +735,22 @@ enum drm_mode_status rcar_du_crtc_mode_valid(struct drm_crtc *crtc,
 	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
 	struct rcar_du_device *rcdu = rcrtc->group->dev;
 	bool interlaced = mode->flags & DRM_MODE_FLAG_INTERLACE;
+	unsigned int vbp;
 
 	if (interlaced && !rcar_du_has(rcdu, RCAR_DU_FEATURE_INTERLACED))
 		return MODE_NO_INTERLACE;
 
+	/*
+	 * The hardware requires a minimum combined horizontal sync and back
+	 * porch of 20 pixels and a minimum vertical back porch of 3 lines.
+	 */
+	if (mode->htotal - mode->hsync_start < 20)
+		return MODE_HBLANK_NARROW;
+
+	vbp = (mode->vtotal - mode->vsync_end) / (interlaced ? 2 : 1);
+	if (vbp < 3)
+		return MODE_VBLANK_NARROW;
+
 	return MODE_OK;
 }
 
@@ -1002,7 +1011,7 @@ unlock:
 	drm_modeset_drop_locks(&ctx);
 	drm_modeset_acquire_fini(&ctx);
 
-	return 0;
+	return ret;
 }
 
 static const struct drm_crtc_funcs crtc_funcs_gen2 = {
@@ -1113,9 +1122,16 @@ int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int swindex,
 	clk = devm_clk_get(rcdu->dev, clk_name);
 	if (!IS_ERR(clk)) {
 		rcrtc->extclock = clk;
-	} else if (PTR_ERR(rcrtc->clock) == -EPROBE_DEFER) {
-		dev_info(rcdu->dev, "can't get external clock %u\n", hwindex);
+	} else if (PTR_ERR(clk) == -EPROBE_DEFER) {
 		return -EPROBE_DEFER;
+	} else if (rcdu->info->dpll_mask & BIT(hwindex)) {
+		/*
+		 * DU channels that have a display PLL can't use the internal
+		 * system clock and thus require an external clock.
+		 */
+		ret = PTR_ERR(clk);
+		dev_err(rcdu->dev, "can't get dclkin.%u: %d\n", hwindex, ret);
+		return ret;
 	}
 
 	init_waitqueue_head(&rcrtc->flip_wait);