[Intel-gfx] [PATCH 2/2] drm/i915: Prevent concurrent tiling/framebuffer modifications

[Chris Wilson]

On Tue, Feb 28, 2017 at 04:22:33PM +0000, Chris Wilson wrote:
> Reintroduce a lock around tiling vs framebuffer creation to prevent
> modification of the obj->tiling_and_stride whilst the framebuffer is
> being created. Rather than use struct_mutex once again, use the
> per-object lock - this will also be required in future to prevent
> changing the tiling whilst submitting rendering.

It also means that we can't create a framebuffer whilst submitting
rendering to/from the object (on this or other device). However, the
gen2/gen3 fence requirement means that we will want some serialisation
between set_tiling_ioctl and execbuffer_ioctl - and so the ww_mutex
still seems apt.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre