drm/kms: add page flipping ioctl

This adds a page flipping ioctl to the KMS API.  The ioctl takes an fb ID
and a ctrc ID and flips the crtc to the given fb at the next vblank.
The ioctl returns immediately but the flip doesn't happen until after
any rendering that's currently queued up against the new framebuffer
is done.  After submitting a page flip, any execbuffer involving the
old front buffer will block until the flip is completed.

Optionally, a vblank event can be generated when the swap eventually
happens.

Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index b69347b8904f..4cc8a32dc4cf 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -290,6 +290,7 @@ struct drm_property {
 struct drm_crtc;
 struct drm_connector;
 struct drm_encoder;
+struct drm_pending_vblank_event;
 
 /**
  * drm_crtc_funcs - control CRTCs for a given device
@@ -333,6 +334,19 @@ struct drm_crtc_funcs {
         void (*destroy)(struct drm_crtc *crtc);
 
         int (*set_config)(struct drm_mode_set *set);
+
+        /*
+         * Flip to the given framebuffer.  This implements the page
+         * flip ioctl descibed in drm_mode.h, specifically, the
+         * implementation must return immediately and block all
+         * rendering to the current fb until the flip has completed.
+         * If userspace set the event flag in the ioctl, the event
+         * argument will point to an event to send back when the flip
+         * completes, otherwise it will be NULL.
+         */
+        int (*page_flip)(struct drm_crtc *crtc,
+                         struct drm_framebuffer *fb,
+                         struct drm_pending_vblank_event *event);
 };
 
 /**
@@ -756,6 +770,8 @@ extern int drm_mode_gamma_get_ioctl(struct drm_device *dev,
 extern int drm_mode_gamma_set_ioctl(struct drm_device *dev,
                                     void *data, struct drm_file *file_priv);
 extern bool drm_detect_hdmi_monitor(struct edid *edid);
+extern int drm_mode_page_flip_ioctl(struct drm_device *dev,
+                                    void *data, struct drm_file *file_priv);
 extern struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
                                 int hdisplay, int vdisplay, int vrefresh,
                                 bool reduced, bool interlaced, bool margins);