[PATCH 1/3] drm/i915: implement dma buf begin_cpu_access

[Daniel Vetter]

On Mon, Jul 30, 2012 at 02:06:54PM +1000, Dave Airlie wrote:
> From: Dave Airlie <airlied at redhat.com>
> 
> In order for udl vmap to work properly, we need to push the object
> into the CPU domain before we start copying the data to the USB device.
> 
> question: what is direction here in terms of read/write to the device.
> 
> This along with the udl change avoids userspace explicit mapping to
> be used.
> 
> Signed-off-by: Dave Airlie <airlied at redhat.com>

In my understanding TO_DEVICE means cpu writes, devices reads. FROM is
devices writes, cpu reads. So your patch looks correct.

One thing I wonder is how much lockdep likes this one here ... But I guess
it's not the first one ;-) Also, do we have a simple testcase that clears
the bo with the intel igd and then tells udl the updated damage, just to
exercise the code a bit?
-Daniel
-- 
Daniel Vetter
Mail: daniel at ffwll.ch
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