The future of Xephyr and Kdriver

[Kristian Høgsberg]

On Mon, Nov 8, 2010 at 11:01 AM, Jamey Sharp <jamey at minilop.net> wrote:
> On Mon, Nov 8, 2010 at 1:45 AM, Feng, Haitao <haitao.feng at intel.com> wrote:
>> Have you noticed Kristian's Wayland project? In an email discussion,
>> Kristian mentioned the "Xorg on Xorg" idea and discussed its design and
>> implementation. Quoted from the email:
>>
>> "I imagine a new module called 'hosted' that lets the DDX drivers detect
>> that they're running under an existing display server (Xorg or wayland)
>> and then use that instead of KMS for modesetting and allocating front
>> buffers.  Ideally this can be done in a way so that the DDX driver
>> doesn't need to know what the host display server is, but just
>> interfaces with the 'hosted' module.  Then there will be a little bit of
>> code that each DDX driver needs to add that talks to the 'hosted' module
>> to get the DRM fd, to set the front buffer and to post damage."
>
> That's fascinating. I haven't heard Kristian mention the 'hosted'
> module idea before.
>
> That approach should get great performance for nested displays, and
> sounds fairly easy to implement. It only works if both servers are
> running on the same machine though. Obviously that's an important use
> case, and covers what you need for Meego. It doesn't address several
> other use cases we care about, where there are one or more backend X
> servers on different machines.
>
> Our project will go ahead on a pure X basis. If somebody builds this
> 'hosted' module, maybe at some point in the future we could find a way
> for the two to cooperate. Something like, if the backend server has
> working DRI2 then try loading the hosted and hardware drivers
> automatically?

I already wrote it:

  http://cgit.freedesktop.org/~krh/xserver/log/?h=hosted

Right now that only supports Xorg on wayland, but I've started
separating out the backend, to let it run on either wayland or Xorg.

Kristian