[X2Go-User] New x2go broken on Ubuntu 17.10

Mihai Moldovan ionic at ionic.de
Sun Dec 24 00:50:38 CET 2017


* On 12/23/2017 09:04 AM, Robert Dinse wrote:
>       Ok, I just tried it with lxde, and with lxde display 1 works properly. 
> With the new libs the nightly build worked properly until a few days ago when 
> there were updates to many of the x2go components.  So there is an aspect 
> specific to Mate.  But Mate worked properly with the previous version and works 
> properly locally.  I'm running Mate on my local workstation as well, which is
> also Ubuntu 17.10.

There's definitely something amiss. My results differ from yours, but I think I
have found out why that is.


Running either XFCE or MATE with the *new* nx-libs version resulted in the
following environment:

ionic at ubuntu:~$ cat /tmp/.x2go-ionic/C-ionic-50-1514044160_stDXFCE_dp24/options
nx/nx,[...],geometry=800x600,resize=1,fullscreen=0,[...]:50
ionic at ubuntu:~$ xrandr
Screen 0: minimum 320 x 240, current 800 x 600, maximum 1920 x 1200
NX1 connected 1920x1080+0+0 0mm x 0mm
   nx_1920x1080  60.00*

That just isn't right. The returned screen resolution should match the visual
window dimensions (i.e., 1920x1080 or a bit lower iff window decorations are
used on the local machine), not the initial geometry passed via options (i.e.,
800x600).

MATE tries to make the best out of this situation and maps the 800x600 virtual
screen size to a 1920x1080 physical display resolution, resulting in a very high
DPI value (that, weirdly, will not show up in xdpyinfo or the like).

If you set the DPI value manually in MATE's font settings, this will override
the workaround MATE employs to some degree, but not completely. The actual
screen size is still limited in a non-trivial way and maximizing a window within
the session will lead to very odd results.

XFCE behaves differently, but also faces the same problem. Here, instead of
simulating a high DPI value, the screen is split into smaller 800x600
"sections". Applications can not be maximized to any bigger value than the
first/top left 800x600 section, while, interestingly, the dock/bottom panel
floats at the bottom of the screen as it should and is not confined to the first
800x600 section only. The top panel also stretches over all sections.

In all my tests, I have so far been unable to actually change the virtual screen
size. That's probably what I need to look into next.


The situation is different for the old, legacy version of nx-libs: the session
is opened seemingly in fullscreen (it's really just "fake fullscreen", but bear
with me), but the viewport is only 800x600 in size.

Resizing is possible via XFCE's display utility (selecting a resolution of
1920x1080), which then sticks and is probably the reason for it working in your
case - you must have done so some time ago. In a clean environment, this wasn't
the case of course. For MATE, the situation is more bleak, since MATE's display
utility depends upon XRANDR 1.3+, which the old nx-libs version does not
provide. Hence, the only possibility to resize the session is to use the xrandr
tool and the XRANDR 1.1/1.0 interface (i.e., -s). Xrandr 1.2 (--output ...
--mode ...) fails in RRGetScreenResourcesCurrent. This change of course is only
temporary and will not be saved upon session termination.

Example output of xrandr:

ionic at ubuntu:~$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 320 x 240, current 800 x 600, maximum 1920 x 1200
default connected 800x600+0+0 0mm x 0mm
   [a lot of other modes I don't care about]
   800x600       60.00*
   [a lot of other modes I don't care about]


Note, that, if you're testing on an unclean, upgraded system and already have
set a custom resolution in MATE itself previously (I guess that older MATE
versions didn't require XRANDR 1.3+ yet), then you probably side-stepped this issue.



Mihai

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 898 bytes
Desc: OpenPGP digital signature
URL: <http://lists.x2go.org/pipermail/x2go-user/attachments/20171224/92c18224/attachment.sig>


More information about the x2go-user mailing list