Re: [PATCH 14/16] drm/i915: Remove locking for get_tiling

Joonas Lahtinen
2016-08-04T10:41:00Z

On ma, 2016-08-01 at 19:22 +0100, Chris Wilson wrote:
> 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 can use the lower

s/, / /,s/can/could/

With that,

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Regards, Joonas
--
Joonas Lahtinen
Open Source Technology Center
Intel Corporation