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 <[email protected]>
Tested-by: Maud Spierings <[email protected]>
Tested-by: Diederik de Haas <[email protected]>  # NanoPC-T6 LTS, Rock 5B
Signed-off-by: Cristian Ciocaltea <[email protected]>
---
 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 3377ea936120..9544eb8659aa 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

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