On Tue, Feb 13, 2024 at 01:30:58PM +0200, Jani Nikula wrote:
> Clarify the conditions for choosing the MST mode to use by adding a new
> function intel_dp_mst_mode_choose(). This also prepares for being able
> to extend the MST modes to single-stream sideband messaging.
>
> Cc: Arun R Murthy <arun.r.murthy@xxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 25 +++++++++++++++++++------
> 1 file changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 944f566525dd..007cb2a04e38 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4015,6 +4015,24 @@ static const char *intel_dp_mst_mode_str(enum drm_dp_mst_mode mst_mode)
> return str_yes_no(mst_mode == DRM_DP_MST);
> }
>
> +static enum drm_dp_mst_mode
> +intel_dp_mst_mode_choose(struct intel_dp *intel_dp,
> + enum drm_dp_mst_mode sink_mst_mode)
> +{
> + struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +
> + if (!i915->display.params.enable_dp_mst)
> + return DRM_DP_SST;
> +
> + if (!intel_dp_mst_source_support(intel_dp))
> + return DRM_DP_SST;
> +
> + if (sink_mst_mode == DRM_DP_SST_SIDEBAND_MSG)
> + return DRM_DP_SST;
> +
> + return sink_mst_mode;
> +}
> +
> static bool
> intel_dp_mst_detect(struct intel_dp *intel_dp)
> {
> @@ -4025,12 +4043,7 @@ intel_dp_mst_detect(struct intel_dp *intel_dp)
>
> sink_mst_mode = drm_dp_read_mst_cap(&intel_dp->aux, intel_dp->dpcd);
>
> - if (i915->display.params.enable_dp_mst &&
> - intel_dp_mst_source_support(intel_dp) &&
> - sink_mst_mode == DRM_DP_MST)
> - mst_detect = DRM_DP_MST;
> - else
> - mst_detect = DRM_DP_SST;
> + mst_detect = intel_dp_mst_mode_choose(intel_dp, sink_mst_mode);
>
> drm_dbg_kms(&i915->drm,
> "[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam: %s -> enable: %s\n",
> --
> 2.39.2
--
Ville Syrjälä
Intel
