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Commit 899526d9 authored by Jesse Barnes's avatar Jesse Barnes Committed by Keith Packard
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drm/i915/dp: try to read receiver capabilities 3 times when detecting 



If ->detect is called too soon after a hot plug event, the sink may not
be ready yet.  So try up to 3 times with 1ms sleeps in between tries to
get the data (spec dictates that receivers must be ready to respond within
1ms and that sources should try 3 times).

See section 9.1 of the 1.1a DisplayPort spec.

Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: default avatarKeith Packard <keithp@keithp.com>
Signed-off-by: default avatarKeith Packard <keithp@keithp.com>
parent 59cd09e1

drivers/gpu/drm/i915/intel_dp.c

+10 −5
Original line number Diff line number Diff line
@@ -1551,6 +1551,7 @@ static enum drm_connector_status 
ironlake_dp_detect(struct intel_dp *intel_dp)

{

	enum drm_connector_status status;

	int ret, i;



	/* Can't disconnect eDP, but you can close the lid... */

	if (is_edp(intel_dp)) {
@@ -1561,12 +1562,16 @@ ironlake_dp_detect(struct intel_dp *intel_dp) 
	}



	status = connector_status_disconnected;

	if (intel_dp_aux_native_read(intel_dp,

	for (i = 0; i < 3; i++) {

		ret = intel_dp_aux_native_read(intel_dp,

					       0x000, intel_dp->dpcd,

				     sizeof (intel_dp->dpcd))

	    == sizeof(intel_dp->dpcd)) {

		if (intel_dp->dpcd[DP_DPCD_REV] != 0)

					       sizeof (intel_dp->dpcd));

		if (ret == sizeof(intel_dp->dpcd) &&

		    intel_dp->dpcd[DP_DPCD_REV] != 0) {

			status = connector_status_connected;

			break;

		}

		msleep(1);

	}

	DRM_DEBUG_KMS("DPCD: %hx%hx%hx%hx\n", intel_dp->dpcd[0],

		      intel_dp->dpcd[1], intel_dp->dpcd[2], intel_dp->dpcd[3]);