linux/drivers/gpu
Archit Taneja b03e14fd4b drm/omap: Take a fb reference in omap_plane_update()
When userspace calls SET_PLANE ioctl, drm core takes a reference of the fb and
passes control to the update_plane op defined by the drm driver.

In omapdrm, we have a worker thread which queues framebuffers objects received
from update_plane and displays them at the appropriate time.

It is possible that the framebuffer is destoryed by userspace between the time
of calling the ioctl and apply-worker being scheduled. If this happens, the
apply-worker holds a pointer to a framebuffer which is already destroyed.

Take an extra refernece/unreference of the fb in omap_plane_update() to prevent
this from happening. A reference is taken of the fb passed to update_plane(),
the previous framebuffer (held by plane->fb) is unreferenced. This will prevent
drm from destroying the framebuffer till the time it's unreferenced by the
apply-worker.

This is in addition to the exisitng reference/unreference in update_pin(),
which is taken for the scanout of the plane's current framebuffer, and an
unreference the previous framebuffer.

Signed-off-by: Archit Taneja <archit@ti.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
2013-04-11 13:25:57 +03:00
..
drm drm/omap: Take a fb reference in omap_plane_update() 2013-04-11 13:25:57 +03:00
vga fbcon: fix locking harder 2013-02-08 12:02:43 +10:00
Makefile gpu: remove gma500 stub driver 2013-02-20 17:54:58 +10:00