[PATCH] drm/udl: avoid swiotlb for imported vmap buffers.

[Dave Airlie]

>>
>> However if we don't set a dma mask on the usb device, the mapping
>> ends up using swiotlb on machines that have it enabled, which
>> is less than desireable.
>>
>> Signed-off-by: Dave Airlie <airlied at redhat.com>
>
> Fyi for everyone else who was not on irc when Dave&I discussed this:
> This really shouldn't be required and I think the real issue is that
> udl creates a dma_buf attachement (which is needed for device dma
> only), but only really wants to do cpu access through vmap/kmap. So
> not attached the device should be good enough. Cc'ing a few more lists
> for better fyi ;-)

Though I've looked at this a bit more, and since I want to be able to expose
shared objects as proper GEM objects from the import side I really
need that list of pages.

So it looks like this won't really fly.

Dave.