Xpra: Ticket #2681: Black screen on xpra start-desktop :1 --use-display

The exact command line is:

xpra start-desktop :1 --use-display --no-speaker --no-microphone --clipboard=no --bind-tcp=0.0.0.0:47503 --html=on

Well, it's not totally black, I see the small menu on the top-left corner and I can launch processes from there (I see them with ps). But everything else is black in the browser screen (both with Firefox and Chrome, with both users).

This is a freshly created user, on my main user xpra works ok in this same way. I've logged in on the other user, so he has it's own DISPLAY.

xpra version is v3.0.7-r25627 on Ubuntu 18.04 64-bit on 4.15.0-91-generic



Wed, 25 Mar 2020 12:59:51 GMT - aviopene: attachment set


Wed, 25 Mar 2020 13:01:03 GMT - Antoine Martin: status, description changed; resolution set

What are you expecting to see? If you want to start an application or a desktop environment, add:

--start=xterm

or

--start=fluxbox

Or whatever.


Wed, 25 Mar 2020 14:02:31 GMT - aviopene: status changed; resolution deleted

Added --start=xterm at the end of the command line:

xpra start-desktop :1 --use-display --no-speaker --no-microphone --clipboard=no --bind-tcp=0.0.0.0:47503 --html=on --start=xterm

Same black screen. As I wrote, the desktop works because I can launch as many calculators as I want and I see them with ps. The rest of screen remains black.


Wed, 25 Mar 2020 14:30:13 GMT - Antoine Martin: owner, status changed

Wait, why are you using :1 and --use-display? What are you trying to do? Is this your existing X11 display?

In which case, you want xpra shadow, not xpra start-desktop.


Wed, 25 Mar 2020 15:01:42 GMT - aviopene:

Replying to Antoine Martin:

Wait, why are you using :1 and --use-display? What are you trying to do? Is this your existing X11 display?

I have :0 for my main user and :1 for another user freshly created. I'm trying to sync another Dropbox account but the only way to do selective sync is to have the damn dropbox icon in the tray and xpra is steadily improving in performance and ease of use, so I was trying to use it instead of the plethora of DBUS_SESSION_BUS_ADDRESS="", dbus-launch tricks, etc. that Dropbox requires to show in the notification bar.

In which case, you want xpra shadow, not xpra start-desktop.

With:

xpra shadow :1 --use-display --no-speaker --no-microphone --clipboard=no --bind-tcp=0.0.0.0:47504 --html=on

I see the same black screen, but now if I attach via ssh, I also see the mouse pointer :)


Wed, 25 Mar 2020 15:08:53 GMT - Antoine Martin:

If :1 is a regular display managed by your X11 server, you probably won't be able to see anything when this display is not active.

Why not just forward the dropbox tray icon alone via xpra? xpra start ssh://user2@localhost/ --start=dropbox


Wed, 25 Mar 2020 16:30:12 GMT - aviopene: status changed; resolution set

Replying to Antoine Martin:

If :1 is a regular display managed by your X11 server, you probably won't be able to see anything when this display is not active.

Yep, you're right, I've already noticed this problem, the screen must be "in use" for xpra to show something or for xwd -root to capture something.

Why not just forward the dropbox tray icon alone via xpra? xpra start ssh://user2@localhost/ --start=dropbox

Thanks I'll try, for the moment I've solved trying all the dropbox dbus tricks with bruteforce and one of them worked.

This doesn't look like a xpra problem, I can mark this bug as fixed, I don't know if "upstream" is more appropriate.

Thanks!


Sat, 23 Jan 2021 05:57:57 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/2681