Re: [PATCH v8 11/39] drm/display: hdmi-state-helper: Set HDMI scrambling requirement

[Maxime Ripard]

On Thu, Jul 02, 2026 at 05:46:24PM +0300, Cristian Ciocaltea wrote:
> 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.
> 
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/display/drm_hdmi_state_helper.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> index 69ccfbf123fe..34e48e04d971 100644
> --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> @@ -592,6 +592,7 @@ hdmi_compute_clock(const struct drm_connector *connector,
>  		return -EINVAL;
>  
>  	conn_state->hdmi.tmds_char_rate = clock;
> +	conn_state->hdmi.scrambler_needed = (clock > HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);

I'd add a FIXME/TODO comment that we might want to check
drm_display_info.hdmi.scdc.scrambling.low_rates

With that fixed,
Acked-by: Maxime Ripard <mripard@xxxxxxxxxx>

Maxime

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