[PATCH v8 27/29] drm/msm/dp: ignore IRQ HPD latched together with an unplug

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

IRQ HPD can be reported with a plug or unplug event.

For unplug + IRQ HPD, ignore the IRQ because the link is being torn
down and the IRQ may be stale.

Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 40b2f6e120cf..8e30420a017f 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1131,7 +1131,10 @@ static irqreturn_t msm_dp_display_irq_thread(int irq, void *dev_id)
 		drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
 				      connector_status_connected);
 
-	if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK)
+	/* Do not access a link torn down by an unplug latched after an IRQ. */
+	if ((hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) &&
+	    (!(hpd_isr_status & DP_DP_HPD_UNPLUG_INT_MASK) ||
+	     (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK)))
 		drm_bridge_hpd_notify_extra(dp->msm_dp_display.bridge,
 					    connector_status_connected,
 					    DRM_CONNECTOR_DP_IRQ_HPD);

-- 
2.43.0