[PATCH] drm/i915/display: Fixed the main link lost in MST

[Jani Nikula]

On Thu, 25 Apr 2024, gareth.yu at intel.com wrote:
> From: Gareth Yu <gareth.yu at intel.com>
>
> Re-train the main link when the sink asserts a HPD for the main lnk
> lost.

NAK.

Please read the review comments.

BR,
Jani.

>
> v4:  detect the main link state by intel_dp_needs_link_retrain
>      instead of intel_dp_mst_link_status because the main link
>      state can't detect correctly sometimes by
>      intel_dp_mst_link_status
>
> Cc : Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay at intel.com>
> Cc : Matt Roper <matthew.d.roper at intel.com>
> Cc : Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Gareth Yu <gareth.yu at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index e05e25cd4a94..e1b60303b256 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5849,8 +5849,14 @@ intel_dp_detect(struct drm_connector *connector,
>  	/* Can't disconnect eDP */
>  	if (intel_dp_is_edp(intel_dp))
>  		status = edp_detect(intel_dp);
> -	else if (intel_digital_port_connected(encoder))
> +	else if (intel_digital_port_connected(encoder)) {
>  		status = intel_dp_detect_dpcd(intel_dp);
> +		if (status == connector_status_connected && intel_dp->is_mst &&
> +		    intel_dp_needs_link_retrain(intel_dp)) {
> +			if (intel_dp_retrain_link(encoder, ctx))
> +				status = connector_status_disconnected;
> +		}
> +	}
>  	else
>  		status = connector_status_disconnected;

-- 
Jani Nikula, Intel