[PATCH v3 weston] compositor-drm: update internal cursor plane location when disabling cursor

[Derek Foreman]

When the cursor plane is disabled the kernel can lose its location.
If we don't update our internal idea of where the plane is at that time,
the next time we set a cursor it can show up at 0,0.

This can show up when an application is put in the cursor plane, removed
from the plane, then put back at the same location.  It might show up at
0,0 when it's reinstated.

We now use INT32_MIN as a location for disabled cursors so enabling the
plane will always cause an update.

Reviewed-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
Signed-off-by: Derek Foreman <derekf at osg.samsung.com>
---
Changes from v1:
use INT32_MIN instead of 0

Changes from v2:
actually init the cursor plane to INT32_MIN, INT32_MIN

 src/compositor-drm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index 8b9882e..7666862 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -1174,6 +1174,8 @@ drm_output_set_cursor(struct drm_output *output)
 	output->cursor_view = NULL;
 	if (ev == NULL) {
 		drmModeSetCursor(b->drm.fd, output->crtc_id, 0, 0, 0);
+		output->cursor_plane.x = INT32_MIN;
+		output->cursor_plane.y = INT32_MIN;
 		return;
 	}
 
@@ -2430,7 +2432,8 @@ create_output_for_connector(struct drm_backend *b,
 	output->base.gamma_size = output->original_crtc->gamma_size;
 	output->base.set_gamma = drm_output_set_gamma;
 
-	weston_plane_init(&output->cursor_plane, b->compositor, 0, 0);
+	weston_plane_init(&output->cursor_plane, b->compositor,
+			  INT32_MIN, INT32_MIN);
 	weston_plane_init(&output->fb_plane, b->compositor, 0, 0);
 
 	weston_compositor_stack_plane(b->compositor, &output->cursor_plane, NULL);
-- 
2.7.0