[PATCH v2] drm: support hotspot for universal plane cursors

[John Keeping]

The request's hot_x and hot_y are set correctly for both
DRM_IOCTL_MODE_CURSOR and DRM_IOCTL_MODE_CURSOR2 so we just need to save
the values and then apply the offset to the cursor plane when the cursor
moves.

Signed-off-by: John Keeping <john at metanate.com>
---
v2:
  - add kerneldoc for hot_x and hot_y in struct drm_crtc

 drivers/gpu/drm/drm_crtc.c | 11 +++++++----
 include/drm/drm_crtc.h     |  6 ++++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 720a153..40f5b84 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2831,6 +2831,9 @@ static int drm_mode_cursor_universal(struct drm_crtc *crtc,
 				DRM_DEBUG_KMS("failed to wrap cursor buffer in drm framebuffer\n");
 				return PTR_ERR(fb);
 			}
+
+			crtc->hot_x = req->hot_x;
+			crtc->hot_y = req->hot_y;
 		} else {
 			fb = NULL;
 		}
@@ -2841,11 +2844,11 @@ static int drm_mode_cursor_universal(struct drm_crtc *crtc,
 	}
 
 	if (req->flags & DRM_MODE_CURSOR_MOVE) {
-		crtc_x = req->x;
-		crtc_y = req->y;
+		crtc_x = req->x - crtc->hot_x;
+		crtc_y = req->y - crtc->hot_y;
 	} else {
-		crtc_x = crtc->cursor_x;
-		crtc_y = crtc->cursor_y;
+		crtc_x = crtc->cursor_x - crtc->hot_x;
+		crtc_y = crtc->cursor_y - crtc->hot_y;
 	}
 
 	if (fb) {
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 3f0c690..2be4414 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -404,6 +404,8 @@ struct drm_crtc_funcs {
  * @cursor: cursor plane for this CRTC
  * @cursor_x: current x position of the cursor, used for universal cursor planes
  * @cursor_y: current y position of the cursor, used for universal cursor planes
+ * @hot_x: x-coordinate of cursor hotspot, used for universal cursor planes
+ * @hot_y: y-coordinate of cursor hotspot, used for universal cursor planes
  * @enabled: is this CRTC enabled?
  * @mode: current mode timings
  * @hwmode: mode timings as programmed to hw regs
@@ -445,6 +447,10 @@ struct drm_crtc {
 	int cursor_x;
 	int cursor_y;
 
+	/* hotspot of cursor */
+	int hot_x;
+	int hot_y;
+
 	bool enabled;
 
 	/* Requested mode from modesetting. */
-- 
2.6.3.462.gbe2c914