How to support mixed DPI in Xwayland?

Adam Jackson ajax at
Tue Sep 12 18:13:40 UTC 2017

On Tue, 2017-09-12 at 19:34 +0200, Joseph Burt wrote:
> On Mon, Sep 11, 2017 at 3:44 PM, Adam Jackson <ajax at> wrote:
> > 
> > Root window size is only ever sent during the initial connection
> > handshake, and the client extension libraries don't update it when the
> > root window is reconfigured [2]. So we have a bootstrapping problem:
> > how is the X server supposed to know which set of lies to give the
> > client when it connects? If you have multiple displays (either logical
> > views or whole processes) then you decide this when you connect, and
> > remote X apps [3] have an obvious way to pick the right one.
> Could this be done with one server listening on two sockets? This
> could work for X servers in general, has it been discussed in that
> context?

"Two sockets" is what I meant by "logical views", there. Depending
which socket you connect to, you'd get different connection handshake
data and different coordinate scalings, but would otherwise interact
with the same set of objects. Again, easy enough to describe, not so
easy to actually implement.

- ajax

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