[Intel-gfx] [PATCH v2 02/12] drm/i915/dp: Respect the sink's max TMDS clock when dealing with DP->HDMI DFPs

[Shankar, Uma]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville Syrjala
> Sent: Tuesday, March 22, 2022 5:30 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH v2 02/12] drm/i915/dp: Respect the sink's max TMDS
> clock when dealing with DP->HDMI DFPs
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Currently we only look at the DFPs max TMDS clock limit when considering whether
> the mode is valid, or whether we can do deep color. The sink's max TMDS clock limit
> may be lower than the DFPs, so we need to account for it as well.

Looks Good to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4095
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2844
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 24 +++++++++++++++++++-----
>  1 file changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index e874d2f78088..3394e4951fef 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -856,20 +856,34 @@ static bool intel_dp_hdisplay_bad(struct drm_i915_private
> *dev_priv,
>  	return hdisplay == 4096 && !HAS_DDI(dev_priv);  }
> 
> +static int intel_dp_max_tmds_clock(struct intel_dp *intel_dp) {
> +	struct intel_connector *connector = intel_dp->attached_connector;
> +	const struct drm_display_info *info = &connector->base.display_info;
> +	int max_tmds_clock = intel_dp->dfp.max_tmds_clock;
> +
> +	/* Only consider the sink's max TMDS clock if we know this is a HDMI DFP */
> +	if (max_tmds_clock && info->max_tmds_clock)
> +		max_tmds_clock = min(max_tmds_clock, info->max_tmds_clock);
> +
> +	return max_tmds_clock;
> +}
> +
>  static enum drm_mode_status
>  intel_dp_tmds_clock_valid(struct intel_dp *intel_dp,
>  			  int clock, int bpc, bool ycbcr420_output)  {
> -	int tmds_clock;
> +	int tmds_clock, min_tmds_clock, max_tmds_clock;
> 
>  	tmds_clock = intel_hdmi_tmds_clock(clock, bpc, ycbcr420_output);
> 
> -	if (intel_dp->dfp.min_tmds_clock &&
> -	    tmds_clock < intel_dp->dfp.min_tmds_clock)
> +	min_tmds_clock = intel_dp->dfp.min_tmds_clock;
> +	max_tmds_clock = intel_dp_max_tmds_clock(intel_dp);
> +
> +	if (min_tmds_clock && tmds_clock < min_tmds_clock)
>  		return MODE_CLOCK_LOW;
> 
> -	if (intel_dp->dfp.max_tmds_clock &&
> -	    tmds_clock > intel_dp->dfp.max_tmds_clock)
> +	if (max_tmds_clock && tmds_clock > max_tmds_clock)
>  		return MODE_CLOCK_HIGH;
> 
>  	return MODE_OK;
> --
> 2.34.1