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

[Dave Airlie]

On Tue, May 7, 2013 at 1:59 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Mon, May 06, 2013 at 10:35:35AM +1000, Dave Airlie wrote:
>> >>
>> >> 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.
>
> Hm, what does "proper GEM object" mean in the context of udl?

One that appears the same as a GEM object created by userspace. i.e. mmap works.

Dave.