XWayland / glamor on virtual machines

Thomas Hellstrom thellstrom at vmware.com
Wed Nov 12 03:24:56 PST 2014

On 11/12/2014 11:57 AM, Pekka Paalanen wrote:
> On Tue, 11 Nov 2014 15:52:53 +0100
> Thomas Hellstrom <thellstrom at vmware.com> wrote:
>> Hi!
>> I was just starting out to try out XWayland in fedora 21 on top of
>> gnome/wayland + vmwgfx.
>> Currently no text is rendered, I'm not sure whether this is a glamor bug
>> or a vmwgfx GL bug, but in any case, I suspect that using glamor for
>> xrender acceleration will be very slow, and something we'd like to
>> avoid. (The overhead of setting up accelerated state and allocating
>> surfaces on vmwgfx will probably just be too high. But I'll need to get
>> back with hard figures).
>> What we would like to do is to use something like SAA, that we are using
>> in the vmware DDX today, basically we avoid accelerating xrender and
>> just accelerate copy / composite stuff that originates from the 3D
>> driver, and that already resides on the host, to avoid readbacks.
>> Does anybody have a strong feeling against us adding something like that
>> to XWayland? As I see it, it could probably be implemented in various
>> ways: It might be possible to reuse parts of Glamor for those operations
>> where we need to accelerate. It should also be possible to implement
>> something device-independent for gallium drivers on top of XA.
>> Any feedback appreciated.
> Hi,
> sorry, I know nothing about the Xwayland internal architecture. I'm not
> even sure we have any way to configure Xwayland.
> Can you autodetect everything at runtime, or would there be some
> configuration involved?
> Thanks,
> pq


Right now there is a command line option for XWayland to use
software-only rendering. That works OK, but will obviously not work with
DRI apps. Adding another command-line option would be one way, but I
guess there would be various other ways we could detect at run-time what
GL / EGL driver is running and base the decision on that.


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