openwrt/target/linux/bcm27xx/patches-5.15/950-0632-drm-vc4-hdmi-Take-the-sink-maximum-TMDS-clock-into-a.patch

From e63d40712a11de18ea217c2211dfd3ae937bab7f Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Mon, 13 Dec 2021 15:33:11 +0100
Subject: [PATCH] drm/vc4: hdmi: Take the sink maximum TMDS clock into
 account

In the function that validates that the clock isn't too high, we've only
taken our controller limitations into account so far.

However, the sink can have a limit on the maximum TMDS clock it can deal
with too which is exposed through the EDID and the drm_display_info.

Make sure we check it.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1254,12 +1254,18 @@ static enum drm_mode_status
 vc4_hdmi_encoder_clock_valid(const struct vc4_hdmi *vc4_hdmi,
 			     unsigned long long clock)
 {
+	const struct drm_connector *connector = &vc4_hdmi->connector;
+	const struct drm_display_info *info = &connector->display_info;
+
 	if (clock > vc4_hdmi->variant->max_pixel_clock)
 		return MODE_CLOCK_HIGH;
 
 	if (vc4_hdmi->disable_4kp60 && clock > HDMI_14_MAX_TMDS_CLK)
 		return MODE_CLOCK_HIGH;
 
+	if (info->max_tmds_clock && clock > (info->max_tmds_clock * 1000))
+		return MODE_CLOCK_HIGH;
+
 	return MODE_OK;
 }