[PATCH v10 20/69] drm/display: hdmi-state-helper: Add source TMDS rate validation

[Cristian Ciocaltea]

Validate the computed TMDS character rate against
connector->hdmi.max_tmds_char_rate, when provided by the driver/source.

This gives HDMI connectors common support for rejecting modes whose TMDS
character rate exceeds the source supported limit, while still allowing
drivers with custom validation requirements to implement their own
tmds_char_rate_valid() callback.

Tested-by: Maud Spierings <maud_spierings at hotmail.com>
Tested-by: Diederik de Haas <diederik at cknow-tech.com>  # NanoPC-T6 LTS, Rock 5B
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea at collabora.com>
---
 drivers/gpu/drm/display/drm_hdmi_state_helper.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index ce17eeefc2da..92be6278ea44 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -560,6 +560,10 @@ hdmi_clock_valid(const struct drm_connector *connector,
 	if (info->max_tmds_clock && clock > info->max_tmds_clock * 1000)
 		return MODE_CLOCK_HIGH;
 
+	if (connector->hdmi.max_tmds_char_rate &&
+	    clock > connector->hdmi.max_tmds_char_rate)
+		return MODE_CLOCK_HIGH;
+
 	if (funcs && funcs->tmds_char_rate_valid) {
 		enum drm_mode_status status;
 

-- 
2.55.0