[PATCH] qxl: rewrite framebuffer support

[Dave Airlie]

On 5 May 2015 at 21:52, Gerd Hoffmann <kraxel at redhat.com> wrote:
> Completely different approach:  Instead of encoding each and every
> framebuffer update as spice operation simply update the shadow
> framebuffer and maintain a dirty rectangle.  Also schedule a worker
> to push an update for the dirty rectangle as spice operation.  Usually
> a bunch of dirty rectangle updates are collected before the worker
> actually runs.
>
> What changes:  Updates get batched now.  Instead of sending tons of
> small updates a few large ones are sent.  When the same region is
> updated multiple times within a short timeframe (scrolling multiple
> lines for example) we send a single update only.  Spice server has an
> easier job now:  The dependency tree for display operations which spice
> server maintains for lazy rendering is alot smaller now.  Spice server's
> image compression probably works better too with the larger image blits.
>
> Net effect:  framebuffer console @ qxldrmfb is an order of magnitude
> faster now.
>
> Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>

Looks good, I often wondered if we should have done this, spice
protocol overhead
seemed quite high.

I'll merge this into drm-next.

Dave.