[PATCH 4.2 40/54] drm/qxl: fix framebuffer dirty rectangle tracking.

Greg Kroah-Hartman
2015-10-23T17:47:31Z

From: Gerd Hoffmann <kraxel@redhat.com>

commit 60906529bec506a4bde93f04eb5e7a9dd9c42a3b upstream.

Commit "c0fe07a drm/qxl: rewrite framebuffer support" has a bug in the
dirty rectangle tracking: Instead of ignoring an empty dirty rectangle
when adding a new dirty region the dirty region gets extended to the
upper left corner. Fix it.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/qxl/qxl_fb.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

--- a/drivers/gpu/drm/qxl/qxl_fb.c
+++ b/drivers/gpu/drm/qxl/qxl_fb.c
@@ -144,14 +144,17 @@ static void qxl_dirty_update(struct qxl_

spin_lock_irqsave(&qfbdev->dirty.lock, flags);

- if (qfbdev->dirty.y1 < y)
- y = qfbdev->dirty.y1;
- if (qfbdev->dirty.y2 > y2)
- y2 = qfbdev->dirty.y2;
- if (qfbdev->dirty.x1 < x)
- x = qfbdev->dirty.x1;
- if (qfbdev->dirty.x2 > x2)
- x2 = qfbdev->dirty.x2;
+ if ((qfbdev->dirty.y2 - qfbdev->dirty.y1) &&
+ (qfbdev->dirty.x2 - qfbdev->dirty.x1)) {
+ if (qfbdev->dirty.y1 < y)
+ y = qfbdev->dirty.y1;
+ if (qfbdev->dirty.y2 > y2)
+ y2 = qfbdev->dirty.y2;
+ if (qfbdev->dirty.x1 < x)
+ x = qfbdev->dirty.x1;
+ if (qfbdev->dirty.x2 > x2)
+ x2 = qfbdev->dirty.x2;
+ }

qfbdev->dirty.x1 = x;
qfbdev->dirty.x2 = x2;