Commit c4e3170a authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/i915: Allow MST sinks to work even if drm_probe_ddc() fails 



With HSW + Dell UP2414Q (at least) drm_probe_ddc() occasionally fails,
and then we'll assume that the entire display has been disconnected.
We don't need the EDID from the main link, so we can simply check if
the sink is MST capable, and if so treat is as connected.

v2: Skip drm_probe_ddc() entirely for MST (Daniel)

Cc: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Cc: Jim Bride <jim.bride@linux.intel.com>
Cc: Manasi D Navare <manasi.d.navare@intel.com>
Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1469800276-6979-1-git-send-email-ville.syrjala@linux.intel.com
parent f64425a8

drivers/gpu/drm/i915/intel_dp.c

+30 −15
Original line number Diff line number Diff line
@@ -3545,7 +3545,7 @@ intel_dp_probe_oui(struct intel_dp *intel_dp) 
}



static bool

intel_dp_probe_mst(struct intel_dp *intel_dp)

intel_dp_can_mst(struct intel_dp *intel_dp)

{

	u8 buf[1];
@@ -3558,18 +3558,30 @@ intel_dp_probe_mst(struct intel_dp *intel_dp) 
	if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)

		return false;



	if (drm_dp_dpcd_read(&intel_dp->aux, DP_MSTM_CAP, buf, 1)) {

		if (buf[0] & DP_MST_CAP) {

	if (drm_dp_dpcd_read(&intel_dp->aux, DP_MSTM_CAP, buf, 1) != 1)

		return false;



	return buf[0] & DP_MST_CAP;

}



static void

intel_dp_configure_mst(struct intel_dp *intel_dp)

{

	if (!i915.enable_dp_mst)

		return;



	if (!intel_dp->can_mst)

		return;



	intel_dp->is_mst = intel_dp_can_mst(intel_dp);



	if (intel_dp->is_mst)

		DRM_DEBUG_KMS("Sink is MST capable\n");

			intel_dp->is_mst = true;

		} else {

	else

		DRM_DEBUG_KMS("Sink is not MST capable\n");

			intel_dp->is_mst = false;

		}

	}



	drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);

	return intel_dp->is_mst;

	drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr,

					intel_dp->is_mst);

}



static int intel_dp_sink_crc_stop(struct intel_dp *intel_dp)
@@ -3999,6 +4011,9 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp) 
		connector_status_connected : connector_status_disconnected;

	}



	if (intel_dp_can_mst(intel_dp))

		return connector_status_connected;



	/* If no HPD, poke DDC gently */

	if (drm_probe_ddc(&intel_dp->aux.ddc))

		return connector_status_connected;
@@ -4236,7 +4251,6 @@ intel_dp_long_pulse(struct intel_connector *intel_connector) 
	struct drm_device *dev = connector->dev;

	enum drm_connector_status status;

	enum intel_display_power_domain power_domain;

	bool ret;

	u8 sink_irq_vector;



	power_domain = intel_display_port_aux_power_domain(intel_encoder);
@@ -4279,8 +4293,9 @@ intel_dp_long_pulse(struct intel_connector *intel_connector) 


	intel_dp_probe_oui(intel_dp);



	ret = intel_dp_probe_mst(intel_dp);

	if (ret) {

	intel_dp_configure_mst(intel_dp);



	if (intel_dp->is_mst) {

		/*

		 * If we are in MST mode then this connector

		 * won't appear connected or have anything

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