[PATCH 23/36] randr: add initial scanout pixmap support (v2)

[Dave Airlie]

On Tue, Jul 3, 2012 at 12:51 AM, Keith Packard <keithp at keithp.com> wrote:
> Dave Airlie <airlied at gmail.com> writes:
>
>> From: Dave Airlie <airlied at redhat.com>
>>
>> When randr notices a crtc configuration request for a slave device,
>> it checks if the slave allocated pixmap exists and is suitable,
>> if not it allocates a new shared pixmap from the master, shares
>> it to the slave, and starts the master tracking damage to it,
>> to keep it updated from the current front pixmap.
>>
>> If the resize means the crtc is no longer used it will destroy
>> the slave pixmap.
>>
>> This adds the concept of a scanout_pixmap to the randr_crtc object,
>> and also adds a master pixmap pointer to the pixmap object, along
>> with defining some pixmap helper functions for getting pixmap
>> box/regions.
>
> I'd rather store the master pixmap somewhere else; it looks like you
> could stick it in the crtc pretty easily, right next to the
> scanout_pixmap member.
>
> Otherwise, this looks good to me.

The master_pixmap is also used in DRI2 code later for sharing, the last patch.

So it made sense to stick it in the pixmap when I had two users, I
suppose I could
try and stash it somewhere else in each user but it might get a bit ugly.

Dave.