[PATCH 6/6] prime: add rotation support for offloaded outputs

[Dave Airlie]

On 15 June 2015 at 18:02, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Mon, Jun 15, 2015 at 09:25:01AM +1000, Dave Airlie wrote:
>> One of the lacking features with output offloading was
>> that screen rotation didn't work at all.
>>
>> This patch makes 0/90/180/270 rotation work with USB output
>> and GPU outputs.
>>
>> When it allocates the shared pixmap it allocates it rotated,
>> and any updates to the shared pixmap are done using a composite
>> path that does the rotation. The slave GPU then doesn't need
>> to know about the rotation and just displays the pixmap.
>
> This doesn't seem right. The slaved output already has the transform
> details and currently the ability to apply HW transformation when
> possible. It also needs to know the transform for applying the HW
> cursor. I guess the problem you face is that you want the host GPU to
> accelerate the rotation for a slaved USB device?

Yes as otherwise it would be pointless and way too slow.

Dave.