[PATCH v9 18/61] drm/display: hdmi-state-helper: Set HDMI scrambling requirement

[Cristian Ciocaltea]

Set drm_connector_hdmi_state.scrambler_needed when the computed TMDS
character rate exceeds the HDMI 1.3 maximum TMDS character rate.

HDMI 2.0 requires scrambling above 340 MHz.  Centralize that clock-based
requirement in the HDMI state helper so drivers do not need to open-code
the threshold check.

Acked-by: Maxime Ripard <mripard at kernel.org>
Tested-by: Maud Spierings <maud_spierings at hotmail.com>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea at collabora.com>
---
 drivers/gpu/drm/display/drm_hdmi_state_helper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index ad59318a3e85..d112c1555517 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -594,6 +594,9 @@ hdmi_compute_clock(const struct drm_connector *connector,
 
 	conn_state->hdmi.tmds_char_rate = clock;
 
+	/* TODO: also check drm_display_info.hdmi.scdc.scrambling.low_rates */
+	conn_state->hdmi.scrambler_needed = (clock > HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);
+
 	return 0;
 }
 

-- 
2.55.0