[Intel-gfx] [PATCH] drm/i915: Check domains for userptr on release

[Matthew Auld]

On Sun, 31 Mar 2019 at 10:47, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>
> When we return pages to the system, we release control over them and
> should defensively return them to the CPU write domain so that we catch
> any external writes on reacquiring them (e.g. to transparently
> swapout/swapin). While we did this defensive clflushing for ordinary
> shmem pages, it was forgotten for userptr. Fortunately, userptr objects
> are normally cache coherent and so oblivious to the forgotten domain
> tracking.
>
> References: a679f58d0510 ("drm/i915: Flush pages on acquisition")
> References: 754a25442705 ("drm/i915: Skip object locking around a no-op set-domain ioctl")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Matthew Auld <matthew.william.auld at gmail.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Reviewed-by: Matthew Auld <matthew.william.auld at gmail.com>