drm/i915: Avoid a full port detection in the first eDP short pulse (2bb06265) · Commits · 戴 / test

Some eDP panels do not set a valid sink count value and even for the ones that sets is should always be one for eDP, that is why it is not cached in intel_edp_init_dpcd(). But intel_dp_short_pulse() compares the old count with the read one if there is a mistmatch a full port detection will be executed, what was happening in the first short pulse interruption of eDP panels that sets sink count. Instead of just skip the compasison for eDP panels, lets not read the sink count at all for eDP. v2: the previous version of this patch it was caching the sink count in intel_edp_init_dpcd() but I was pointed out by Ville a patch that handled a case of a eDP panel that do not set sink count and as sink count is not used to eDP certification was choosed to just not read it at all. Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com> Reviewed-by:

Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by:

José Roberto de Souza <jose.souza@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181121225441.18785-1-jose.souza@intel.com

drivers/gpu/drm/i915/intel_dp.c

+26 −18

Original line number	Diff line number	Diff line
		@@ -3936,8 +3936,6 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
		static bool
		intel_dp_get_dpcd(struct intel_dp *intel_dp)
		{
		u8 sink_count;

		if (!intel_dp_read_dpcd(intel_dp))
		return false;

		@@ -3947,7 +3945,16 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
		intel_dp_set_common_rates(intel_dp);
		}

		if (drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_COUNT, &sink_count) <= 0)
		/*
		* Some eDP panels do not set a valid value for sink count, that is why
		* it don't care about read it here and in intel_edp_init_dpcd().
		*/
		if (!intel_dp_is_edp(intel_dp)) {
		u8 count;
		ssize_t r;

		r = drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_COUNT, &count);
		if (r < 1)
		return false;

		/*
		@@ -3955,7 +3962,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
		* a member variable in intel_dp will track any changes
		* between short pulse interrupts.
		*/
		intel_dp->sink_count = DP_GET_SINK_COUNT(sink_count);
		intel_dp->sink_count = DP_GET_SINK_COUNT(count);

		/*
		* SINK_COUNT == 0 and DOWNSTREAM_PORT_PRESENT == 1 implies that
		@@ -3964,8 +3971,9 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
		* downstream port information. So, an early return here saves
		* time from performing other operations which are not required.
		*/
		if (!intel_dp_is_edp(intel_dp) && !intel_dp->sink_count)
		if (!intel_dp->sink_count)
		return false;
		}

		if (!drm_dp_is_branch(intel_dp->dpcd))
		return true; /* native DP sink */

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