drm/amdgpu: Retry DDC probing on DVI on failure if we got an HPD interrupt

HPD signals on DVI ports can be fired off before the pins required for
DDC probing actually make contact, due to the pins for HPD making
contact first. This results in a HPD signal being asserted but DDC
probing failing, resulting in hotplugging occasionally failing.

Rescheduling the hotplug work for a second when we run into an HPD
signal with a failing DDC probe usually gives enough time for the rest
of the connector's pins to make contact, and fixes this issue.
Signed-off-by: xurui <xurui@kylinos.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -876,7 +876,7 @@ struct amdgpu_device {
 	struct amdgpu_vkms_output       *amdgpu_vkms_output;
 	struct amdgpu_mode_info		mode_info;
 	/* For pre-DCE11. DCE11 and later are in "struct amdgpu_device->dm" */
-	struct work_struct		hotplug_work;
+	struct delayed_work         hotplug_work;
 	struct amdgpu_irq_src		crtc_irq;
 	struct amdgpu_irq_src		vline0_irq;
 	struct amdgpu_irq_src		vupdate_irq;

drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c

@@ -996,13 +996,33 @@ amdgpu_connector_dvi_detect(struct drm_connector *connector, bool force)
 		}
 	}
 
+	if (amdgpu_connector->detected_hpd_without_ddc) {
+		force = true;
+		amdgpu_connector->detected_hpd_without_ddc = false;
+	}
+
 	if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
 		ret = connector->status;
 		goto exit;
 	}
 
-	if (amdgpu_connector->ddc_bus)
+	if (amdgpu_connector->ddc_bus) {
 		dret = amdgpu_display_ddc_probe(amdgpu_connector, false);
+
+		/* Sometimes the pins required for the DDC probe on DVI
+		 * connectors don't make contact at the same time that the ones
+		 * for HPD do. If the DDC probe fails even though we had an HPD
+		 * signal, try again later
+		 */
+		if (!dret && !force &&
+		    amdgpu_display_hpd_sense(adev, amdgpu_connector->hpd.hpd)) {
+			DRM_DEBUG_KMS("hpd detected without ddc, retrying in 1 second\n");
+			amdgpu_connector->detected_hpd_without_ddc = true;
+			schedule_delayed_work(&adev->hotplug_work,
+					      msecs_to_jiffies(1000));
+			goto exit;
+		}
+	}
 	if (dret) {
 		amdgpu_connector->detected_by_load = false;
 		amdgpu_connector_free_edid(connector);

drivers/gpu/drm/amd/amdgpu/amdgpu_display.c

@@ -63,7 +63,7 @@
 void amdgpu_display_hotplug_work_func(struct work_struct *work)
 {
 	struct amdgpu_device *adev = container_of(work, struct amdgpu_device,
-						  hotplug_work);
+						  hotplug_work.work);
 	struct drm_device *dev = adev_to_drm(adev);
 	struct drm_mode_config *mode_config = &dev->mode_config;
 	struct drm_connector *connector;

drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h

@@ -534,6 +534,7 @@ struct amdgpu_connector {
 	void *con_priv;
 	bool dac_load_detect;
 	bool detected_by_load; /* if the connection status was determined by load */
+	bool detected_hpd_without_ddc; /* if an HPD signal was detected on DVI, but ddc probing failed */
 	uint16_t connector_object_id;
 	struct amdgpu_hpd hpd;
 	struct amdgpu_router router;

drivers/gpu/drm/amd/amdgpu/dce_v10_0.c

@@ -2837,7 +2837,7 @@ static int dce_v10_0_sw_init(void *handle)
 	if (r)
 		return r;
 
-	INIT_WORK(&adev->hotplug_work,
+	INIT_DELAYED_WORK(&adev->hotplug_work,
 		  amdgpu_display_hotplug_work_func);
 
 	drm_kms_helper_poll_init(adev_to_drm(adev));
@@ -2902,7 +2902,7 @@ static int dce_v10_0_hw_fini(void *handle)
 
 	dce_v10_0_pageflip_interrupt_fini(adev);
 
-	flush_work(&adev->hotplug_work);
+	flush_delayed_work(&adev->hotplug_work);
 
 	return 0;
 }
@@ -3302,7 +3302,7 @@ static int dce_v10_0_hpd_irq(struct amdgpu_device *adev,
 
 	if (disp_int & mask) {
 		dce_v10_0_hpd_int_ack(adev, hpd);
-		schedule_work(&adev->hotplug_work);
+		schedule_delayed_work(&adev->hotplug_work, 0);
 		DRM_DEBUG("IH: HPD%d\n", hpd + 1);
 	}
 

drivers/gpu/drm/amd/amdgpu/dce_v11_0.c

@@ -2956,7 +2956,7 @@ static int dce_v11_0_sw_init(void *handle)
 	if (r)
 		return r;
 
-	INIT_WORK(&adev->hotplug_work,
+	INIT_DELAYED_WORK(&adev->hotplug_work,
 		  amdgpu_display_hotplug_work_func);
 
 	drm_kms_helper_poll_init(adev_to_drm(adev));
@@ -3032,7 +3032,7 @@ static int dce_v11_0_hw_fini(void *handle)
 
 	dce_v11_0_pageflip_interrupt_fini(adev);
 
-	flush_work(&adev->hotplug_work);
+	flush_delayed_work(&adev->hotplug_work);
 
 	return 0;
 }
@@ -3426,7 +3426,7 @@ static int dce_v11_0_hpd_irq(struct amdgpu_device *adev,
 
 	if (disp_int & mask) {
 		dce_v11_0_hpd_int_ack(adev, hpd);
-		schedule_work(&adev->hotplug_work);
+		schedule_delayed_work(&adev->hotplug_work, 0);
 		DRM_DEBUG("IH: HPD%d\n", hpd + 1);
 	}
 

drivers/gpu/drm/amd/amdgpu/dce_v6_0.c

@@ -2715,7 +2715,7 @@ static int dce_v6_0_sw_init(void *handle)
 		return r;
 
 	/* Pre-DCE11 */
-	INIT_WORK(&adev->hotplug_work,
+	INIT_DELAYED_WORK(&adev->hotplug_work,
 		  amdgpu_display_hotplug_work_func);
 
 	drm_kms_helper_poll_init(adev_to_drm(adev));
@@ -2776,7 +2776,7 @@ static int dce_v6_0_hw_fini(void *handle)
 
 	dce_v6_0_pageflip_interrupt_fini(adev);
 
-	flush_work(&adev->hotplug_work);
+	flush_delayed_work(&adev->hotplug_work);
 
 	return 0;
 }
@@ -3103,7 +3103,7 @@ static int dce_v6_0_hpd_irq(struct amdgpu_device *adev,
 		tmp = RREG32(mmDC_HPD1_INT_CONTROL + hpd_offsets[hpd]);
 		tmp |= DC_HPD1_INT_CONTROL__DC_HPD1_INT_ACK_MASK;
 		WREG32(mmDC_HPD1_INT_CONTROL + hpd_offsets[hpd], tmp);
-		schedule_work(&adev->hotplug_work);
+		schedule_delayed_work(&adev->hotplug_work, 0);
 		DRM_DEBUG("IH: HPD%d\n", hpd + 1);
 	}
 

drivers/gpu/drm/amd/amdgpu/dce_v8_0.c

@@ -2739,7 +2739,7 @@ static int dce_v8_0_sw_init(void *handle)
 		return r;
 
 	/* Pre-DCE11 */
-	INIT_WORK(&adev->hotplug_work,
+	INIT_DELAYED_WORK(&adev->hotplug_work,
 		  amdgpu_display_hotplug_work_func);
 
 	drm_kms_helper_poll_init(adev_to_drm(adev));
@@ -2802,7 +2802,7 @@ static int dce_v8_0_hw_fini(void *handle)
 
 	dce_v8_0_pageflip_interrupt_fini(adev);
 
-	flush_work(&adev->hotplug_work);
+	flush_delayed_work(&adev->hotplug_work);
 
 	return 0;
 }
@@ -3195,7 +3195,7 @@ static int dce_v8_0_hpd_irq(struct amdgpu_device *adev,
 		tmp = RREG32(mmDC_HPD1_INT_CONTROL + hpd_offsets[hpd]);
 		tmp |= DC_HPD1_INT_CONTROL__DC_HPD1_INT_ACK_MASK;
 		WREG32(mmDC_HPD1_INT_CONTROL + hpd_offsets[hpd], tmp);
-		schedule_work(&adev->hotplug_work);
+		schedule_delayed_work(&adev->hotplug_work, 0);
 		DRM_DEBUG("IH: HPD%d\n", hpd + 1);
 	}