[Spice-devel] New xrandr multi-mon / arbitrary resolution support issues

[Marc-André Lureau]

On Sun, Aug 26, 2012 at 5:29 PM, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi,
>
> On 08/26/2012 03:48 PM, Hans de Goede wrote:
>>
>> Hi,
>>
>> As part of integrating the spice-vdagent xrandr patches
>> (done, as there were many other patches pending, so fixes
>> can just be applied on top), I've been testing the new
>> xrandr multi-mon / arbitrary resolution support.
>>
>> With single monitor setups, things work fine, but with
>> multiple monitor setups things don't work as advertised.
>>
>
> Ok, so the problem was thatI thought that all changes except for
> the xorg-x11-drv-qxl changes were upstream, and thus having the latest
> master from all was enough, that is not the case, I needed to
> pull in the qemu changes, then all the problems I was seeing are
> gone, but instead there are some new ones:
>
> 1) when enabling a new display through remote-viewer the initial
> resolution is no good, it should be something sensible, maybe the
> same size as the existing display?

What is sensible? Can you explain your reasoning?

> 2) When using --full-screen=auto-conf both windows get shown
> on the same real monitor, so the user in essence sees only one
> as they cover eachother, also to match, they both get
> send to the guest as being 1920x1080+0+0 for both, making the
> guest think they are in clone mode, even if you leave fullscreen,
> and reposition the windows to have one on each monitor

I suppose the client has multiple monitors. That might be a bug (we
have similar issues with existing code), I will try to look at it.

> 3) When making resolution changes from within the guest,
> remote-viewer resizes then sends a resolution change event to
> the guest, which can lead to getting another resolution then
> requested. I believe that remote-viewer should not send
> monitorinfo messages when receiving a resize over the display
> channel.

There are 2 schools:
1. allow window resizing, in which case, the guest can reconfigure the
window size any time (can lead to very large windows, or intermittent
resizes etc.)
2. never resize client window automatically, and avoid scaling: the
client will try to resize-guest whenever it doesn't fit well

In general, the GNOME guideline follows 2: only the user is managing
the windows size.

However, I think we should improve the fullscreen case, and allow
scaling when the guest change resolution. But it will be more
difficult to deal with cases where user switches between window and
fullscreen, as we will have to try to restore the same resolution
somehow.
-- 
Marc-André Lureau