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* [PATCH] drm/vc4: hdmi: Block odd horizontal timings
@ 2020-09-25 13:00 ` Maxime Ripard
  0 siblings, 0 replies; 10+ messages in thread
From: Maxime Ripard @ 2020-09-25 13:00 UTC (permalink / raw)
  To: Daniel Vetter, David Airlie, Maarten Lankhorst,
	Thomas Zimmermann, Maxime Ripard, Eric Anholt
  Cc: Tim Gover, Dave Stevenson, dri-devel, bcm-kernel-feedback-list,
	linux-rpi-kernel, Phil Elwell, linux-arm-kernel

The FIFO between the pixelvalve and the HDMI controller runs at 2 pixels
per clock cycle, and cannot deal with odd timings.

Let's reject any mode with such timings.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 12 ++++++++++++
 drivers/gpu/drm/vc4/vc4_hdmi.h |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 1c4dc774d56e..acfb4e235214 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -879,6 +879,11 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
 	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
 	unsigned long long pixel_rate = mode->clock * 1000;
 
+	if (vc4_hdmi->variant->broken_odd_h_timings &&
+	    ((mode->hdisplay % 2) || (mode->hsync_start % 2) ||
+	     (mode->hsync_end % 2) || (mode->htotal % 2)))
+		return -EINVAL;
+
 	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
 		pixel_rate *= 2;
 
@@ -901,6 +906,11 @@ vc4_hdmi_encoder_mode_valid(struct drm_encoder *encoder,
 {
 	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
 
+	if (vc4_hdmi->variant->broken_odd_h_timings &&
+	    ((mode->hdisplay % 2) || (mode->hsync_start % 2) ||
+	     (mode->hsync_end % 2) || (mode->htotal % 2)))
+		return MODE_H_ILLEGAL;
+
 	if ((mode->clock * 1000) > vc4_hdmi->variant->max_pixel_clock)
 		return MODE_CLOCK_HIGH;
 
@@ -1950,6 +1960,7 @@ static const struct vc4_hdmi_variant bcm2711_hdmi0_variant = {
 		PHY_LANE_2,
 		PHY_LANE_CK,
 	},
+	.broken_odd_h_timings	= true,
 
 	.init_resources		= vc5_hdmi_init_resources,
 	.csc_setup		= vc5_hdmi_csc_setup,
@@ -1975,6 +1986,7 @@ static const struct vc4_hdmi_variant bcm2711_hdmi1_variant = {
 		PHY_LANE_CK,
 		PHY_LANE_2,
 	},
+	.broken_odd_h_timings	= true,
 
 	.init_resources		= vc5_hdmi_init_resources,
 	.csc_setup		= vc5_hdmi_csc_setup,
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index af45b0d81dec..40e51ece8efe 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -62,6 +62,9 @@ struct vc4_hdmi_variant {
 	 */
 	enum vc4_hdmi_phy_channel phy_lane_mapping[4];
 
+	/* The BCM2711 cannot deal with odd horizontal pixel timings */
+	bool broken_odd_h_timings;
+
 	/* Callback to get the resources (memory region, interrupts,
 	 * clocks, etc) for that variant.
 	 */
-- 
2.26.2


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^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2020-10-30  8:25 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-25 13:00 [PATCH] drm/vc4: hdmi: Block odd horizontal timings Maxime Ripard
2020-09-25 13:00 ` Maxime Ripard
2020-10-28 13:42 ` Dave Stevenson
2020-10-28 13:42   ` Dave Stevenson
2020-10-29  9:17   ` Maxime Ripard
2020-10-29  9:17     ` Maxime Ripard
2020-10-29 10:49     ` Dave Stevenson
2020-10-29 10:49       ` Dave Stevenson
2020-10-29 12:26       ` Maxime Ripard
2020-10-29 12:26         ` Maxime Ripard

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