[Intel-gfx] [RFC 13/15] drm/i915/hdmi21/mtl: Enable Scrambling only for FRL mode

[Ankit Nautiyal <ankit.k.nautiyal@intel.com>]

In FRL mode, the Scrambling is always enabled by the HW.
The High TMDS Char Rate and Scrambing Enable bit of
reg TRANS_DDI_FUNC_CTRL are only set in TMDS mode and not
in FRL mode.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdmi.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 1dd0b0f2e2f1..1eadf77dc819 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2292,7 +2292,13 @@ int intel_hdmi_compute_config(struct intel_encoder *encoder,
 
 	pipe_config->lane_count = 4;
 
-	if (scdc->scrambling.supported && DISPLAY_VER(dev_priv) >= 10) {
+	/*
+	 * Enable scrambing for only for TMDS mode.
+	 * For FRL mode, scrambling is always enabled by HW, and
+	 * scrambling enable and high tmds clock bits are not used.
+	 */
+	if (scdc->scrambling.supported && DISPLAY_VER(dev_priv) >= 10 &&
+	    !pipe_config->frl.enable) {
 		if (scdc->scrambling.low_rates)
 			pipe_config->hdmi_scrambling = true;
 
-- 
2.25.1