Commit e41e992c authored by Imre Deak's avatar Imre Deak
Browse files

drm/i915/dp_mst: Fix forced link retrain handling in MST HPD IRQ handler 



Handling of a forced link retraining debugfs request via the DP MST HPD
IRQ handler is incorrectly skipped, if the IRQ handler doesn't see any
HPD IRQs raised by the sink. Fix this by ensuring that the request is
always handled (in the Fixes: commit below by directly calling
intel_dp_check_link_state(), later by the same call moved to
intel_dp_handle_link_service_irq()).

Cc: Luca Coelho <luciano.coelho@intel.com>
Fixes: db4855d9 ("drm/i915/dp_mst: Reuse intel_dp_check_link_state() in the HPD IRQ handler")
Reviewed-by: default avatarSuraj Kandpal <suraj.kandpal@intel.com>
Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260311153152.133744-1-imre.deak@intel.com
parent 5f6da193

drivers/gpu/drm/i915/display/intel_dp.c

+13 −3
Original line number Diff line number Diff line
@@ -5575,11 +5575,13 @@ static bool 
intel_dp_check_mst_status(struct intel_dp *intel_dp)

{

	struct intel_display *display = to_intel_display(intel_dp);

	bool force_retrain = intel_dp->link.force_retrain;

	bool reprobe_needed = false;



	for (;;) {

		u8 esi[4] = {};

		u8 ack[4] = {};

		bool new_irqs;



		if (!intel_dp_get_sink_irq_esi(intel_dp, esi)) {

			drm_dbg_kms(display->drm,
@@ -5595,20 +5597,28 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp) 


		intel_dp_mst_hpd_irq(intel_dp, esi, ack);



		if (mem_is_zero(ack, sizeof(ack)))

			break;

		new_irqs = !mem_is_zero(ack, sizeof(ack));



		drm_WARN_ON(display->drm, ack[1] & ~INTEL_DP_DEVICE_SERVICE_IRQ_MASK_MST);

		drm_WARN_ON(display->drm, ack[3] & ~INTEL_DP_LINK_SERVICE_IRQ_MASK_MST);



		if (!intel_dp_ack_sink_irq_esi(intel_dp, ack))

		if (new_irqs && !intel_dp_ack_sink_irq_esi(intel_dp, ack))

			drm_dbg_kms(display->drm, "Failed to ack ESI\n");



		if (ack[1] & (DP_DOWN_REP_MSG_RDY | DP_UP_REQ_MSG_RDY))

			drm_dp_mst_hpd_irq_send_new_request(&intel_dp->mst.mgr);



		if (force_retrain) {

			/* Defer forced retraining to the regular link status check. */

			ack[3] |= LINK_STATUS_CHANGED;

			force_retrain = false;

		}



		if (intel_dp_handle_link_service_irq(intel_dp, ack[3]))

			reprobe_needed = true;



		if (!new_irqs)

			break;

	}



	return !reprobe_needed;