2 files changed, 22 insertions, 10 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index e9befb6d10fd..0f18b76c7906 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -456,14 +456,6 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
 
         WARN_ON_ONCE(dlist_next - dlist_start != vc4_state->mm.size);
 
-        HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
-                  vc4_state->mm.start);
-
-        if (debug_dump_regs) {
-                DRM_INFO("CRTC %d HVS after:\n", drm_crtc_index(crtc));
-                vc4_hvs_dump_state(dev);
-        }
-
         if (crtc->state->event) {
                 unsigned long flags;
 
@@ -473,8 +465,20 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
 
                 spin_lock_irqsave(&dev->event_lock, flags);
                 vc4_crtc->event = crtc->state->event;
-                spin_unlock_irqrestore(&dev->event_lock, flags);
                 crtc->state->event = NULL;
+
+                HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
+                          vc4_state->mm.start);
+
+                spin_unlock_irqrestore(&dev->event_lock, flags);
+        } else {
+                HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
+                          vc4_state->mm.start);
+        }
+
+        if (debug_dump_regs) {
+                DRM_INFO("CRTC %d HVS after:\n", drm_crtc_index(crtc));
+                vc4_hvs_dump_state(dev);
         }
 }
 
@@ -500,10 +504,14 @@ static void vc4_crtc_handle_page_flip(struct vc4_crtc *vc4_crtc)
 {
         struct drm_crtc *crtc = &vc4_crtc->base;
         struct drm_device *dev = crtc->dev;
+        struct vc4_dev *vc4 = to_vc4_dev(dev);
+        struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);
+        u32 chan = vc4_crtc->channel;
         unsigned long flags;
 
         spin_lock_irqsave(&dev->event_lock, flags);
-        if (vc4_crtc->event) {
+        if (vc4_crtc->event &&
+            (vc4_state->mm.start == HVS_READ(SCALER_DISPLACTX(chan)))) {
                 drm_crtc_send_vblank_event(crtc, vc4_crtc->event);
                 vc4_crtc->event = NULL;
                 drm_crtc_vblank_put(crtc);
diff --git a/drivers/gpu/drm/vc4/vc4_regs.h b/drivers/gpu/drm/vc4/vc4_regs.h
index 6163b95c5411..f99eece4cc97 100644
--- a/drivers/gpu/drm/vc4/vc4_regs.h
+++ b/drivers/gpu/drm/vc4/vc4_regs.h
@@ -341,6 +341,10 @@
 #define SCALER_DISPLACT0                        0x00000030
 #define SCALER_DISPLACT1                        0x00000034
 #define SCALER_DISPLACT2                        0x00000038
+#define SCALER_DISPLACTX(x)                     (SCALER_DISPLACT0 +     \
+                                                 (x) * (SCALER_DISPLACT1 - \
+                                                        SCALER_DISPLACT0))
+
 #define SCALER_DISPCTRL0                        0x00000040
 # define SCALER_DISPCTRLX_ENABLE                BIT(31)
 # define SCALER_DISPCTRLX_RESET                 BIT(30)