linux/drivers/gpu
Tormod Volden 66aa6962ff drm: Compare only lower 32 bits of framebuffer map offsets
Drivers using multiple framebuffers got broken by commit
41c2e75e60 which ignored the framebuffer
(or register) map offset when looking for existing maps. The rationale
was that the kernel-userspace ABI is fixed at a 32-bit offset, so the
real offsets could not always be handed over for comparison.

Instead of ignoring the offset we will compare the lower 32 bit. Drivers
using multiple framebuffers should just make sure that the lower 32 bit
are different. The existing drivers in question are practically limited
to 32-bit systems so that should be fine for them.

It is assumed that current drivers always specify a correct framebuffer
map offset, even if this offset was ignored since above commit. So this
patch should not change anything for drivers using only one framebuffer.

Drivers needing multiple framebuffers with 64-bit map offsets will need
to cook up something, for instance keeping an ID in the lower bit which
is to be aligned away when it comes to using the offset.

All of above applies to _DRM_REGISTERS as well.

Signed-off-by: Tormod Volden <debian.tormod@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-06-14 11:09:54 +10:00
..
drm drm: Compare only lower 32 bits of framebuffer map offsets 2011-06-14 11:09:54 +10:00
stub i915: select VIDEO_OUTPUT_CONTROL for ACPI_VIDEO 2011-04-13 09:10:25 +10:00
vga Merge branch 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2011-05-24 12:06:40 -07:00
Makefile gpu: Add Intel GMA500(Poulsbo) Stub Driver 2010-10-26 11:00:13 +10:00