linux/drivers/gpu
Chris Wilson 9ad3676148 drm/i915: Remove locking for get_tiling
Since we are not concerned with userspace racing itself with set-tiling
(the order is indeterminant even if we take a lock), then we can safely
read back the single obj->tiling_mode and do the static lookup of
swizzle mode without having to take a lock.

get-tiling is reasonably frequent due to the back-channel passing around
of tiling parameters in DRI2/DRI3.

v2: Make tiling_mode a full unsigned int so that we can trivially use it
with READ_ONCE(). Separating it out into manual control over the flags
field was too noisy for a simple patch. Note that we could use the lower
bits of obj->stride for the tiling mode.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470388464-28458-16-git-send-email-chris@chris-wilson.co.uk
2016-08-05 10:54:42 +01:00
..
drm drm/i915: Remove locking for get_tiling 2016-08-05 10:54:42 +01:00
host1x gpu: host1x: Remove useless local variable 2016-06-23 11:59:33 +02:00
ipu-v3 gpu: ipu-v3: ipu-dc: don't bug out on invalid bus_format 2016-07-12 18:26:05 +02:00
vga vga_switcheroo: Sphinxify docs 2016-07-12 16:14:36 +02:00
Makefile