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Commit 61da5fab authored by Jesse Barnes's avatar Jesse Barnes Committed by Keith Packard
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drm/i915/dp: retry link status read 3 times on failure 



Especially after a hotplug or power status change, the sink may not
reply immediately to a link status query.  So retry 3 times per the spec
to really make sure nothing is there.

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 fe0d4220

drivers/gpu/drm/i915/intel_dp.c

+13 −7
Original line number Diff line number Diff line
@@ -1019,14 +1019,20 @@ intel_dp_dpms(struct drm_encoder *encoder, int mode) 
static bool

intel_dp_get_link_status(struct intel_dp *intel_dp)

{

	int ret;

	int ret, i;



	/* Must try AUX reads for this at least 3 times */

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

		ret = intel_dp_aux_native_read(intel_dp,

					       DP_LANE0_1_STATUS,

				       intel_dp->link_status, DP_LINK_STATUS_SIZE);

	if (ret != DP_LINK_STATUS_SIZE)

		return false;

					       intel_dp->link_status,

					       DP_LINK_STATUS_SIZE);

		if (ret == DP_LINK_STATUS_SIZE)

			return true;

		msleep(1);

	}



	return false;

}



static uint8_t