3 files changed, 54 insertions, 6 deletions

diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
index ed47d67cecd6..68db42f15086 100644
--- a/drivers/gpu/drm/vkms/vkms_crc.c
+++ b/drivers/gpu/drm/vkms/vkms_crc.c
@@ -34,6 +34,15 @@ out:
         return crc;
 }
 
+/**
+ * vkms_crc_work_handle - ordered work_struct to compute CRC
+ *
+ * @work: work_struct
+ *
+ * Work handler for computing CRCs. work_struct scheduled in
+ * an ordered workqueue that's periodically scheduled to run by
+ * _vblank_handle() and flushed at vkms_atomic_crtc_destroy_state().
+ */
 void vkms_crc_work_handle(struct work_struct *work)
 {
         struct vkms_crtc_state *crtc_state = container_of(work,
@@ -45,8 +54,18 @@ void vkms_crc_work_handle(struct work_struct *work)
                                                 output);
         struct vkms_crc_data *primary_crc = NULL;
         struct drm_plane *plane;
-
         u32 crc32 = 0;
+        u64 frame_start, frame_end;
+        unsigned long flags;
+
+        spin_lock_irqsave(&out->state_lock, flags);
+        frame_start = crtc_state->frame_start;
+        frame_end = crtc_state->frame_end;
+        spin_unlock_irqrestore(&out->state_lock, flags);
+
+        /* _vblank_handle() hasn't updated frame_start yet */
+        if (!frame_start || frame_start == frame_end)
+                goto out;
 
         drm_for_each_plane(plane, &vdev->drm) {
                 struct vkms_plane_state *vplane_state;
@@ -67,7 +86,20 @@ void vkms_crc_work_handle(struct work_struct *work)
         if (primary_crc)
                 crc32 = _vkms_get_crc(primary_crc);
 
-        drm_crtc_add_crc_entry(crtc, true, crtc_state->n_frame, &crc32);
+        frame_end = drm_crtc_accurate_vblank_count(crtc);
+
+        /* queue_work can fail to schedule crc_work; add crc for
+         * missing frames
+         */
+        while (frame_start <= frame_end)
+                drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
+
+out:
+        /* to avoid using the same value for frame number again */
+        spin_lock_irqsave(&out->state_lock, flags);
+        crtc_state->frame_end = frame_end;
+        crtc_state->frame_start = 0;
+        spin_unlock_irqrestore(&out->state_lock, flags);
 }
 
 static int vkms_crc_parse_source(const char *src_name, bool *enabled)
diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 9d0b1a325a78..177bbcb38306 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -22,8 +22,19 @@ static void _vblank_handle(struct vkms_output *output)
                 DRM_ERROR("vkms failure on handling vblank");
 
         if (state && output->crc_enabled) {
-                state->n_frame = drm_crtc_accurate_vblank_count(crtc);
-                queue_work(output->crc_workq, &state->crc_work);
+                u64 frame = drm_crtc_accurate_vblank_count(crtc);
+
+                /* update frame_start only if a queued vkms_crc_work_handle()
+                 * has read the data
+                 */
+                spin_lock(&output->state_lock);
+                if (!state->frame_start)
+                        state->frame_start = frame;
+                spin_unlock(&output->state_lock);
+
+                ret = queue_work(output->crc_workq, &state->crc_work);
+                if (!ret)
+                        DRM_WARN("failed to queue vkms_crc_work_handle");
         }
 
         spin_unlock(&output->lock);
@@ -211,6 +222,7 @@ int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
         drm_crtc_helper_add(crtc, &vkms_crtc_helper_funcs);
 
         spin_lock_init(&vkms_out->lock);
+        spin_lock_init(&vkms_out->state_lock);
 
         vkms_out->crc_workq = alloc_ordered_workqueue("vkms_crc_workq", 0);
 
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 2017a2ccc43d..80af6d3a65e7 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -39,12 +39,14 @@ struct vkms_plane_state {
  * vkms_crtc_state - Driver specific CRTC state
  * @base: base CRTC state
  * @crc_work: work struct to compute and add CRC entries
- * @n_frame: frame number for computed CRC
+ * @n_frame_start: start frame number for computed CRC
+ * @n_frame_end: end frame number for computed CRC
  */
 struct vkms_crtc_state {
         struct drm_crtc_state base;
         struct work_struct crc_work;
-        unsigned int n_frame;
+        u64 frame_start;
+        u64 frame_end;
 };
 
 struct vkms_output {
@@ -59,6 +61,8 @@ struct vkms_output {
         struct workqueue_struct *crc_workq;
         /* protects concurrent access to crc_data */
         spinlock_t lock;
+        /* protects concurrent access to crtc_state */
+        spinlock_t state_lock;
 };
 
 struct vkms_device {