xf86-video-dummy with randr support - is anyone else interested? Alternatives?

[Alan Cox]

> Alternatives? I cannot find any other driver that would act as a virtual 
> screen like xf86-video-dummy, but would provide a RandR-compliant 
> framebuffer for me. I don't think Xephyr, Xdmx, Xvnc, x2x and whatnot 
> others can help me here, Awesome needs to see something as a regular 
> RandR screen next to the built in panel. Or is it possible to fake this 
> display somehow while being forwarded to another Xserver copy?

Actually they can do. The way I have my little one set up for debugging
and devel work is to create separate X server for it and then I can bind
input devices to it or use x2x as well as using the input filters to make
it grab the actual touchscreen. If you want it to just hotplug you'll
need udev rules as well, and depending upon your auth needs possible gdm
scripting.

If you want persistence you could look at making your main desktop bigger
than the display and then using x11vnc to export the undisplayed corner
to the displaylink server ?

> In case any awesome devs are here, would it actually make sense to patch 
> it on awesome side? Which work list is greater?

The big problem with RandR and friends is that the moment you include a
Displaylink device all your 3D vanishes on all the desktops. This is
quite limiting and will force various apps into software rendering or
just not working as they were before. If you use x2x + dual server you
can't move apps between the displaylink device and the main display but
your 3D etc still work.

The proper solution is an X server setup which can handle 2D only DRI
capable devices in multihead by using one of the 3D devices to do
offscreen rendering for the 2D head. That however seems to be a big
project.

Alan