2 files changed, 40 insertions, 4 deletions

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index b1dbb60af99f..a316f7336aeb 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -5402,6 +5402,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
         struct drm_crtc *crtc;
         struct drm_framebuffer *fb = NULL;
         struct drm_pending_vblank_event *e = NULL;
+        u32 target_vblank = 0;
         int ret = -EINVAL;
 
         if (page_flip->flags & ~DRM_MODE_PAGE_FLIP_FLAGS ||
@@ -5415,6 +5416,19 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
         if (!crtc)
                 return -ENOENT;
 
+        if (crtc->funcs->page_flip_target) {
+                int r;
+
+                r = drm_crtc_vblank_get(crtc);
+                if (r)
+                        return r;
+
+                target_vblank = drm_crtc_vblank_count(crtc) +
+                        !(page_flip->flags & DRM_MODE_PAGE_FLIP_ASYNC);
+        } else if (crtc->funcs->page_flip == NULL) {
+                return -EINVAL;
+        }
+
         drm_modeset_lock_crtc(crtc, crtc->primary);
         if (crtc->primary->fb == NULL) {
                 /* The framebuffer is currently unbound, presumably
@@ -5425,9 +5439,6 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
                 goto out;
         }
 
-        if (crtc->funcs->page_flip == NULL)
-                goto out;
-
         fb = drm_framebuffer_lookup(dev, page_flip->fb_id);
         if (!fb) {
                 ret = -ENOENT;
@@ -5468,7 +5479,12 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
         }
 
         crtc->primary->old_fb = crtc->primary->fb;
-        ret = crtc->funcs->page_flip(crtc, fb, e, page_flip->flags);
+        if (crtc->funcs->page_flip_target)
+                ret = crtc->funcs->page_flip_target(crtc, fb, e,
+                                                    page_flip->flags,
+                                                    target_vblank);
+        else
+                ret = crtc->funcs->page_flip(crtc, fb, e, page_flip->flags);
         if (ret) {
                 if (page_flip->flags & DRM_MODE_PAGE_FLIP_EVENT)
                         drm_event_cancel_free(dev, &e->base);
@@ -5481,6 +5497,8 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
         }
 
 out:
+        if (ret)
+                drm_crtc_vblank_put(crtc);
         if (fb)
                 drm_framebuffer_unreference(fb);
         if (crtc->primary->old_fb)
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 44e070800b6d..3c90563e1a54 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -581,6 +581,24 @@ struct drm_crtc_funcs {
                          uint32_t flags);
 
         /**
+         * @page_flip_target:
+         *
+         * Same as @page_flip but with an additional parameter specifying the
+         * absolute target vertical blank period (as reported by
+         * drm_crtc_vblank_count()) when the flip should take effect.
+         *
+         * Note that the core code calls drm_crtc_vblank_get before this entry
+         * point, and will call drm_crtc_vblank_put if this entry point returns
+         * any non-0 error code. It's the driver's responsibility to call
+         * drm_crtc_vblank_put after this entry point returns 0, typically when
+         * the flip completes.
+         */
+        int (*page_flip_target)(struct drm_crtc *crtc,
+                                struct drm_framebuffer *fb,
+                                struct drm_pending_vblank_event *event,
+                                uint32_t flags, uint32_t target);
+
+        /**
          * @set_property:
          *
          * This is the legacy entry point to update a property attached to the