[PATCH] drm/vgem: fix cache synchronization on arm/arm64

[Chris Wilson]

Quoting Sean Paul (2019-07-31 20:23:31)
> On Fri, Jul 19, 2019 at 11:21:53AM +0200, Daniel Vetter wrote:
> > On Wed, Jul 17, 2019 at 02:15:37PM -0700, Rob Clark wrote:
> > > From: Rob Clark <robdclark at chromium.org>
> > > 
> > > drm_cflush_pages() is no-op on arm/arm64.  But instead we can use
> > > dma_sync API.
> > > 
> > > Fixes failures w/ vgem_test.
> > > 
> > > Signed-off-by: Rob Clark <robdclark at chromium.org>
> > > ---
> > > An alternative approach to the series[1] I sent yesterday
> > > 
> > > On the plus side, it keeps the WC buffers and avoids any drm core
> > > changes.  On the minus side, I don't think it will work (at least
> > > on arm64) prior to v5.0[2], so the fix can't be backported very
> > > far.
> > 
> > Yeah seems a lot more reasonable.
> > 
> > Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> Applied to drm-misc-fixes, thanks!

But it didn't actually fix the failures in CI.
-Chris