Issues on remote desktop resize

[Rafael Guimaraes]

Hi guys,

I am currently using TurboVNC Server to create remote sessions on a server and I am connecting through the TurboVNC Java Viewer. When userA creates a VNC session on the server, I am able to connect to the session and resize its window. However, when userB creates a VNC session on the same server, although I am able to connect to the session, I can't resize the client window. I get scroll bars and I am locked to the window size with which the session was created (no resize). Even if I try to choose a different resolution using the client's menu, it gets back to the original size.

The server is the same (CentOS 6), the client is the same (Java client on a Windows machine), even the creation parameters are the same. The only difference is the user that created the session.

Is there anything that may avoid the window resize? Why can I resize one session and can't do the same with the other? Any parameter that blocks this?

Cheers,

Rafael

[DRC]

There is no server-side parameter that blocks remote desktop resizing.
There is a parameter in /etc/turbovncserver-security.conf
(max-desktop-size) that prevents the remote desktop from exceeding a
certain size, but that parameter applies to all sessions, so it wouldn't
explain why one session is resizable and another isn't. If you were
using the Windows native viewer, which stores viewer options separately
for each connection, then the behavior you're describing might make
sense if User A's session was using a different display number than User
B's session (meaning that the viewer might be recalling a different set
of options for each), but the Java viewer doesn't do that. The Java
viewer loads the same set of global options each time it is launched,
and if you modify the options and save them, those new options will be
used for all subsequent connections. Unfortunately, I have no clue what
might be causing the behavior you describe. Here are some things to
check, however:

(1) Verify whether the viewer options are the same between the failing
and successful connections (that is, actually open the Options dialog in
the viewer after connecting to the server session, and verify that
"Remote desktop size" is "Auto". The viewer *should* be using the same
options for both, but perhaps it isn't for some reason.

(2) Run xrandr in both sessions and verify that it produces reasonable
output. This will tell us whether both sessions have a working RANDR
extension.

(3) Try to resize the desktop using xrandr, e.g. "xrandr -s 1024x768".
That will tell us whether it is only remote desktop resizing that is
broken or whether the failing session can't be resized at all.

(4) Check the log of the failing session and see if there are any error
messages related to a failed attempt by the server to resize the desktop.

[Rafael Guimaraes]

Hi again,

I think that the problem may be with gnome. I am using CentOS 6 with gnome 2.28.2. Is there any setting in Gnome that prevents the session to be resized when I drag the mouse on the corner of the java client window? If I manually change the resolution (by setting it at System -> Preferences -> Display, it changes on the fly. The problem is when dragging the corner of the java client window.

Cheers,

Rafael

[DRC]

Have you followed all of the diagnostic procedures I asked you to follow
below? I cannot offer any further advice until I know the answers to
those questions. I use CentOS 6 with GNOME on a daily basis with
TurboVNC, without any problems. There are thousands of deployments of
exactly that configuration worldwide. I don't think the problem is with
GNOME.

On 10/31/17 2:47 PM, Rafael Guimaraes wrote:
> Hi again,
>
> I think that the problem may be with gnome. I am using CentOS 6 with
> gnome 2.28.2. Is there any setting in Gnome that prevents the session to
> be resized when I drag the mouse on the corner of the java client
> window? If I manually change the resolution (by setting it at System ->
> Preferences -> Display, it changes on the fly. The problem is when
> dragging the corner of the java client window.
>
> Cheers,
>
> Rafael
>
>
> 2017-10-31 15:19 GMT-02:00 Rafael Guimaraes <rgu...@gmail.com

> <mailto:rgu...@gmail.com>>:

[DRC]

Also, are you using the latest version of the TurboVNC Server?  There were several resize-related bugs that were fixed in the last few releases, including in 2.1.2.

On 10/31/17 2:47 PM, Rafael Guimaraes wrote:

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[DRC]

It might also be worth trying the latest stable (2.1.x) pre-release
build of the server:

https://turbovnc.org/DeveloperInfo/PreReleases

I stumbled upon a really hard-to-reproduce bug in the desktop resize
logic. In my case, the bug manifested as a segfault, but it isn't hard
for me to imagine how, under certain circumstances, it might manifest as
a failure to resize.

More specifically, the patch against 2.1.2 is:
https://github.com/TurboVNC/turbovnc/commit/ecb74b675db3a6eb5e3efb968a74f72fa796eeea

DRC

On 10/31/17 2:47 PM, Rafael Guimaraes wrote:

> Hi again,
>
> I think that the problem may be with gnome. I am using CentOS 6 with
> gnome 2.28.2. Is there any setting in Gnome that prevents the session to
> be resized when I drag the mouse on the corner of the java client
> window? If I manually change the resolution (by setting it at System ->
> Preferences -> Display, it changes on the fly. The problem is when
> dragging the corner of the java client window.
>
> Cheers,
>
> Rafael
>
>
> 2017-10-31 15:19 GMT-02:00 Rafael Guimaraes <rgu...@gmail.com

> <mailto:rgu...@gmail.com>>: