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Commit 07d3dc18 authored by Adam Jackson's avatar Adam Jackson Committed by Daniel Vetter
Browse files

drm/i915/dp: Be smarter about connection sense for branch devices 



If there's no downstream device, DPCD success is good enough.  If
there's a hotplug-capable downstream device, count the number of
connected sinks in DP_SINK_STATUS and return success if it's non-zero.
Otherwise, probe DDC and report appropriately.

v2: Check DP_SINK_STATUS instead of something unrelated to sink status.

Tested-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarAdam Jackson <ajax@redhat.com>
Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent b091cd92

drivers/gpu/drm/i915/intel_dp.c

+34 −1
Original line number Diff line number Diff line
@@ -2083,11 +2083,44 @@ intel_dp_check_link_status(struct intel_dp *intel_dp) 
	}

}



/* XXX this is probably wrong for multiple downstream ports */

static enum drm_connector_status

intel_dp_detect_dpcd(struct intel_dp *intel_dp)

{

	if (intel_dp_get_dpcd(intel_dp))

	uint8_t *dpcd = intel_dp->dpcd;

	bool hpd;

	uint8_t type;



	if (!intel_dp_get_dpcd(intel_dp))

		return connector_status_disconnected;



	/* if there's no downstream port, we're done */

	if (!(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))

		return connector_status_connected;



	/* If we're HPD-aware, SINK_COUNT changes dynamically */

	hpd = !!(intel_dp->downstream_ports[0] & DP_DS_PORT_HPD);

	if (hpd) {

		uint8_t sink_count;

		if (!intel_dp_aux_native_read_retry(intel_dp, DP_SINK_COUNT,

						    &sink_count, 1))

			return connector_status_unknown;

		sink_count &= DP_SINK_COUNT_MASK;

		return sink_count ? connector_status_connected

				  : connector_status_disconnected;

	}



	/* If no HPD, poke DDC gently */

	if (drm_probe_ddc(&intel_dp->adapter))

		return connector_status_connected;



	/* Well we tried, say unknown for unreliable port types */

	type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;

	if (type == DP_DS_PORT_TYPE_VGA || type == DP_DS_PORT_TYPE_NON_EDID)

		return connector_status_unknown;



	/* Anything else is out of spec, warn and ignore */

	DRM_DEBUG_KMS("Broken DP branch device, ignoring\n");

	return connector_status_disconnected;

}