[PATCH 2/2] drm/amdgpu: Fix dead lock issue for vblank

[Emily.Deng <Emily.Deng@amd.com>]

Always start vblank timer, but only calls vblank function
when vblank is enabled.

This is used to fix the dead lock issue.
When drm_crtc_vblank_off want to disable vblank,
it first get event_lock, and then call hrtimer_cancel,
but hrtimer_cancel want to wait timer handler function finished.
Timer handler also want to aquire event_lock in drm_handle_vblank.

Signed-off-by: Emily.Deng <Emily.Deng@amd.com>
Change-Id: I7d3cfb1202cd030fdcdec3e7483fcc4c9fa8db70
---
 drivers/gpu/drm/amd/amdgpu/dce_virtual.c | 155 +++++++++++------------
 1 file changed, 77 insertions(+), 78 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/dce_virtual.c b/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
index cc93577dee03..8c02ab74c1de 100644
--- a/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
@@ -226,6 +226,74 @@ static const struct drm_crtc_helper_funcs dce_virtual_crtc_helper_funcs = {
 	.get_scanout_position = amdgpu_crtc_get_scanout_position,
 };
 
+static int dce_virtual_pageflip(struct amdgpu_device *adev,
+				unsigned crtc_id)
+{
+	unsigned long flags;
+	struct amdgpu_crtc *amdgpu_crtc;
+	struct amdgpu_flip_work *works;
+
+	amdgpu_crtc = adev->mode_info.crtcs[crtc_id];
+
+	if (crtc_id >= adev->mode_info.num_crtc) {
+		DRM_ERROR("invalid pageflip crtc %d\n", crtc_id);
+		return -EINVAL;
+	}
+
+	/* IRQ could occur when in initial stage */
+	if (amdgpu_crtc == NULL)
+		return 0;
+
+	spin_lock_irqsave(&adev->ddev->event_lock, flags);
+	works = amdgpu_crtc->pflip_works;
+	if (amdgpu_crtc->pflip_status != AMDGPU_FLIP_SUBMITTED) {
+		DRM_DEBUG_DRIVER("amdgpu_crtc->pflip_status = %d != "
+			"AMDGPU_FLIP_SUBMITTED(%d)\n",
+			amdgpu_crtc->pflip_status,
+			AMDGPU_FLIP_SUBMITTED);
+		spin_unlock_irqrestore(&adev->ddev->event_lock, flags);
+		return 0;
+	}
+
+	/* page flip completed. clean up */
+	amdgpu_crtc->pflip_status = AMDGPU_FLIP_NONE;
+	amdgpu_crtc->pflip_works = NULL;
+
+	/* wakeup usersapce */
+	if (works->event)
+		drm_crtc_send_vblank_event(&amdgpu_crtc->base, works->event);
+
+	spin_unlock_irqrestore(&adev->ddev->event_lock, flags);
+
+	drm_crtc_vblank_put(&amdgpu_crtc->base);
+	amdgpu_bo_unref(&works->old_abo);
+	kfree(works->shared);
+	kfree(works);
+
+	return 0;
+}
+
+static enum hrtimer_restart dce_virtual_vblank_timer_handle(struct hrtimer *vblank_timer)
+{
+	struct amdgpu_crtc *amdgpu_crtc = container_of(vblank_timer,
+						       struct amdgpu_crtc, vblank_timer);
+	struct drm_device *ddev = amdgpu_crtc->base.dev;
+	struct amdgpu_device *adev = ddev->dev_private;
+	struct amdgpu_irq_src *source = adev->irq.client[AMDGPU_IRQ_CLIENTID_LEGACY].sources
+		[VISLANDS30_IV_SRCID_SMU_DISP_TIMER2_TRIGGER];
+	int irq_type = amdgpu_display_crtc_idx_to_irq_type(adev,
+						amdgpu_crtc->crtc_id);
+
+	if (amdgpu_irq_enabled(adev, source, irq_type)) {
+		drm_handle_vblank(ddev, amdgpu_crtc->crtc_id);
+		dce_virtual_pageflip(adev, amdgpu_crtc->crtc_id);
+	}
+	hrtimer_start(vblank_timer, ktime_set(0, DCE_VIRTUAL_VBLANK_PERIOD),
+		      HRTIMER_MODE_REL);
+
+	return HRTIMER_NORESTART;
+}
+
 static int dce_virtual_crtc_init(struct amdgpu_device *adev, int index)
 {
 	struct amdgpu_crtc *amdgpu_crtc;
@@ -247,6 +315,14 @@ static int dce_virtual_crtc_init(struct amdgpu_device *adev, int index)
 	amdgpu_crtc->vsync_timer_enabled = AMDGPU_IRQ_STATE_DISABLE;
 	drm_crtc_helper_add(&amdgpu_crtc->base, &dce_virtual_crtc_helper_funcs);
 
+	hrtimer_init(&amdgpu_crtc->vblank_timer,
+		     CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hrtimer_set_expires(&amdgpu_crtc->vblank_timer,
+			    ktime_set(0, DCE_VIRTUAL_VBLANK_PERIOD));
+	amdgpu_crtc->vblank_timer.function =
+		dce_virtual_vblank_timer_handle;
+	hrtimer_start(&amdgpu_crtc->vblank_timer,
+			      ktime_set(0, DCE_VIRTUAL_VBLANK_PERIOD), HRTIMER_MODE_REL);
 	return 0;
 }
 
@@ -476,7 +552,7 @@ static int dce_virtual_hw_fini(void *handle)
 
 	for (i = 0; i<adev->mode_info.num_crtc; i++)
 		if (adev->mode_info.crtcs[i])
-			dce_virtual_set_crtc_vblank_interrupt_state(adev, i, AMDGPU_IRQ_STATE_DISABLE);
+			hrtimer_cancel(&adev->mode_info.crtcs[i]->vblank_timer);
 
 	return 0;
 }
@@ -645,68 +721,6 @@ static void dce_virtual_set_display_funcs(struct amdgpu_device *adev)
 	adev->mode_info.funcs = &dce_virtual_display_funcs;
 }
 
-static int dce_virtual_pageflip(struct amdgpu_device *adev,
-				unsigned crtc_id)
-{
-	unsigned long flags;
-	struct amdgpu_crtc *amdgpu_crtc;
-	struct amdgpu_flip_work *works;
-
-	amdgpu_crtc = adev->mode_info.crtcs[crtc_id];
-
-	if (crtc_id >= adev->mode_info.num_crtc) {
-		DRM_ERROR("invalid pageflip crtc %d\n", crtc_id);
-		return -EINVAL;
-	}
-
-	/* IRQ could occur when in initial stage */
-	if (amdgpu_crtc == NULL)
-		return 0;
-
-	spin_lock_irqsave(&adev_to_drm(adev)->event_lock, flags);
-	works = amdgpu_crtc->pflip_works;
-	if (amdgpu_crtc->pflip_status != AMDGPU_FLIP_SUBMITTED) {
-		DRM_DEBUG_DRIVER("amdgpu_crtc->pflip_status = %d != "
-			"AMDGPU_FLIP_SUBMITTED(%d)\n",
-			amdgpu_crtc->pflip_status,
-			AMDGPU_FLIP_SUBMITTED);
-		spin_unlock_irqrestore(&adev_to_drm(adev)->event_lock, flags);
-		return 0;
-	}
-
-	/* page flip completed. clean up */
-	amdgpu_crtc->pflip_status = AMDGPU_FLIP_NONE;
-	amdgpu_crtc->pflip_works = NULL;
-
-	/* wakeup usersapce */
-	if (works->event)
-		drm_crtc_send_vblank_event(&amdgpu_crtc->base, works->event);
-
-	spin_unlock_irqrestore(&adev_to_drm(adev)->event_lock, flags);
-
-	drm_crtc_vblank_put(&amdgpu_crtc->base);
-	amdgpu_bo_unref(&works->old_abo);
-	kfree(works->shared);
-	kfree(works);
-
-	return 0;
-}
-
-static enum hrtimer_restart dce_virtual_vblank_timer_handle(struct hrtimer *vblank_timer)
-{
-	struct amdgpu_crtc *amdgpu_crtc = container_of(vblank_timer,
-						       struct amdgpu_crtc, vblank_timer);
-	struct drm_device *ddev = amdgpu_crtc->base.dev;
-	struct amdgpu_device *adev = drm_to_adev(ddev);
-
-	drm_handle_vblank(ddev, amdgpu_crtc->crtc_id);
-	dce_virtual_pageflip(adev, amdgpu_crtc->crtc_id);
-	hrtimer_start(vblank_timer, DCE_VIRTUAL_VBLANK_PERIOD,
-		      HRTIMER_MODE_REL);
-
-	return HRTIMER_NORESTART;
-}
-
 static void dce_virtual_set_crtc_vblank_interrupt_state(struct amdgpu_device *adev,
 							int crtc,
 							enum amdgpu_interrupt_state state)
@@ -716,21 +730,6 @@ static void dce_virtual_set_crtc_vblank_interrupt_state(struct amdgpu_device *ad
 		return;
 	}
 
-	if (state && !adev->mode_info.crtcs[crtc]->vsync_timer_enabled) {
-		DRM_DEBUG("Enable software vsync timer\n");
-		hrtimer_init(&adev->mode_info.crtcs[crtc]->vblank_timer,
-			     CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-		hrtimer_set_expires(&adev->mode_info.crtcs[crtc]->vblank_timer,
-				    DCE_VIRTUAL_VBLANK_PERIOD);
-		adev->mode_info.crtcs[crtc]->vblank_timer.function =
-			dce_virtual_vblank_timer_handle;
-		hrtimer_start(&adev->mode_info.crtcs[crtc]->vblank_timer,
-			      DCE_VIRTUAL_VBLANK_PERIOD, HRTIMER_MODE_REL);
-	} else if (!state && adev->mode_info.crtcs[crtc]->vsync_timer_enabled) {
-		DRM_DEBUG("Disable software vsync timer\n");
-		hrtimer_cancel(&adev->mode_info.crtcs[crtc]->vblank_timer);
-	}
-
 	adev->mode_info.crtcs[crtc]->vsync_timer_enabled = state;
 	DRM_DEBUG("[FM]set crtc %d vblank interrupt state %d\n", crtc, state);
 }
-- 
2.25.1

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