> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Ankit
> Nautiyal
> Sent: Tuesday, December 13, 2022 11:21 AM
> To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Subject: [PATCH] drm/i915/hdmi: Go for scrambling only if
> platform supports TMDS clock > 340MHz
>
> There are cases, where devices have an HDMI1.4 retimer, and TMDS clock
> rate is capped to 340MHz via VBT. In such cases scrambling might be
> supported by the platform and an HDMI2.0 sink for lower TMDS rates, but
> not supported by the retimer, causing blankouts.
>
> So avoid enabling scrambling, if the TMDS clock is capped to <= 340MHz.
>
Doesn't this clash with scrambling with low rates?
Thanks and Regards,
Arun R Murthy
--------------------
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_hdmi.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c
> b/drivers/gpu/drm/i915/display/intel_hdmi.c
> index efa2da080f62..c124fe667bc0 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> @@ -2244,6 +2244,11 @@ static bool intel_hdmi_is_cloned(const struct
> intel_crtc_state *crtc_state)
> !is_power_of_2(crtc_state->uapi.encoder_mask);
> }
>
> +static bool source_can_support_scrambling(struct intel_encoder
> +*encoder) {
> + return intel_hdmi_source_max_tmds_clock(encoder) > 340000; }
> +
> int intel_hdmi_compute_config(struct intel_encoder *encoder,
> struct intel_crtc_state *pipe_config,
> struct drm_connector_state *conn_state) @@ -
> 2301,7 +2306,7 @@ int intel_hdmi_compute_config(struct intel_encoder
> *encoder,
>
> pipe_config->lane_count = 4;
>
> - if (scdc->scrambling.supported && DISPLAY_VER(dev_priv) >= 10) {
> + if (scdc->scrambling.supported &&
> +source_can_support_scrambling(encoder)) {
> if (scdc->scrambling.low_rates)
> pipe_config->hdmi_scrambling = true;
>
> --
> 2.25.1
