[winswitch] First time install of xpra: black screen in all windows.

[G.W. Haywood]

Hi there,

Thanks very much for the speedy and helpful response.

On Sat, 11 Sep 2021, Antoine Martin via shifter-users wrote:
> On 11/09/2021 15:13, G.W. Haywood via shifter-users wrote:
>> On Fri, 10 Sep 2021, G.W. Haywood wrote:
>>> ...
>>> I can start an xpra server on the laptop e.g. with DISPLAY=:101, then
>>> start an xterm for that instance, then attach a local xpra client to
>>> display 101 on the laptop and everything is fine.  However if I attach
>>> to the same server from a client on the Pi, I see a window but there's
>>> no content displayed in it - it's completely black.  Apart from that
>>> it's a functioning connection.  I can run commands in the black window
>>> (blindfold), and they are executed and saved in the command history.
>>
>> More information.  I forgot to mention that the window manager on the
>> laptop is fvwm2, which is not negotiable.
> 
> I hope that you're talking about the window manager you're using with
> the laptop's desktop environment, and not that you expect to be able to
> run a window manager with xpra's seamless mode.

Yes, of course.  The point being that it works fine connecting locally
on the laptop using fvwm2 as the laptop's window manager (and using no
other window manager at all for the xpra session).

> If you want to run a window manager on the server side, then you will
> need to use desktop mode ("xpra start-desktop") instead of the seamless
> mode ("xpra start").

I understand.  When working remotely, I need no window manager (nor
even a user's login session) running on the server side.

>> On the Pi3B+ it is normally
>> Fluxbox.  I tried with fvwm on the Pi with exactly the same results.
>>
> I haven't tried it lately on a PI, I've got a 2 and a 3B gathering dust
> somewhere. This used to work fine but it is possible that something
> broke in later versions without anyone noticing.

Very possible, in fact this is what I suspect.  I was hoping someone
on the list might be running this on a Pi.

> The other possibility is that since you've compiled it yourself, you
> haven't enabled enough picture codecs for it to work properly.

Anything like that is very possible.  I'm very unfamiliar with Python,
I don't even know how to enquire which libraries (modules?) are
installed and I find it very confusing that some things seem to be
installed using '(pip|pip3) install' and some using 'apt-get install'.

> The most important one is python pillow, without this library a lot of
> features just don't work well or not at all.

I have never heard of pillow, but AFAICT it is installed on both the
server and the client.  I'm running Debian Buster on the laptop and
something approximating to Raspbian Bullseye on the Pi so I suspect
that is why the versions are so very different.  I say "something
approximating" because earlier in the week I ran 'apt-get full-upgrade'
on the Pi using the "stable" distribution in the sources.list and it
decided that this would be version 11 (Debian's Bullseye).  According
to my wife (who has delved into this quite a bit) there's been no
official announcement from the Raspbery Pi people that Bullseye is
available. :(  Normally I'm emphatically not on the bleeding edge, I
was just trying to get everything up to date before mailing this list.

8<----------------------------------------------------------------------
laptop3:~# >>> pip3 install pillow
Requirement already satisfied: pillow in /usr/lib/python3/dist-packages (5.4.1)

piplus:~# >>> pip3 install pillow
Looking in indexes: https://pypi.org/simple, https://www.piwheels.org/simple
Requirement already satisfied: pillow in /usr/lib/python3/dist-packages (8.1.2)
8<----------------------------------------------------------------------

Again there are confusions resulting largely from the distro packaging, if
in doubt I install everything which looks vaguely like something I need.
For this exercise that amounted to several hundred pakages on each of the
Pi and the laptop...

> Also, you may want to run the client with --opengl=no (or try forcing it
> on with 'yes') as I can't remember the state of the client opengl
> acceleration on PIs, also it may have improved since.

Tried both, same result.

> If the window is completely blank, I would expect to see some errors in
> the server log.

Three attempts to connect below.  On the laptop:

$ xpra start :103
$ DISPLAY=:103 xterm &

On the Pi:

Try 1:
xpra attach ssh://laptop3/103

Try 2:
xpra --opengl=yes attach ssh://laptop3/103

Try 3:
xpra --opengl=no attach ssh://laptop3/103

In all cases the same result - a black window.

Below is laptop3:/tmp/xpra/103/server.log in full for each of the three
attempts.  Please note that the first line of the log really does have
no timestamp, I haven't accidentally truncated it.  Just my opinion,
but the log would be better without the escape sequences - nothing I
see in 'man xpra' makes me think that they might be optional.

I do not know what the 'html-xpra package' might be.  I have failed to
find it using 'apt-cache search' and attempting to install it using
pip or pip3 just gives an error that it can't be found.

8<----------------------------------------------------------------------
failure on /tmp/.X11-unix/X103: [Errno 2] No such file or directory: '/tmp/.X11-unix/X103'
2021-09-11 10:38:21,555 cannot use uinput for virtual devices:
2021-09-11 10:38:21,555  [Errno 19] Failed to open the uinput device: No such device
2021-09-11 10:38:23,197 pointer device emulation using XTest
2021-09-11 10:38:23,264 Error: cannot find the html web root
2021-09-11 10:38:23,264  '/usr/local/share/xpra/www' does not exist
2021-09-11 10:38:23,264  install the html-xpra package
2021-09-11 10:38:23,264 wrote pid 21107 to '/tmp/xpra/103/server.pid'
2021-09-11 10:38:23,290 Warning: failed to create socket directory '/run/xpra'
2021-09-11 10:38:23,291  [Errno 13] Permission denied: '/run/xpra'
2021-09-11 10:38:23,291 created unix domain socket '/tmp/xpra/laptop3-103'
2021-09-11 10:38:23,291 cannot create group socket '/run/xpra/laptop3-103'
2021-09-11 10:38:23,291  [Errno 2] No such file or directory
2021-09-11 10:38:23,292  /run/xpra does not exist
2021-09-11 10:38:23,292 created unix domain socket '/home/ged/.xpra/laptop3-103'
2021-09-11 10:38:23,292 xvfb pid=21111
2021-09-11 10:38:23,361 D-Bus notification forwarding is available
2021-09-11 10:38:23,382 pulseaudio server started with pid 21154
2021-09-11 10:38:23,382  private server socket path:
2021-09-11 10:38:23,382  '/tmp/xpra/103/pulse-103/pulse/native'
2021-09-11 10:38:23,489 watching for applications menu changes in:
2021-09-11 10:38:23,489  '/usr/share/applications'
2021-09-11 10:38:23,490  '/usr/local/share/applications'
2021-09-11 10:38:23,504 Warning: webcam forwarding is disabled
2021-09-11 10:38:23,504  the virtual video directory '/sys/devices/virtual/video4linux' was not found
2021-09-11 10:38:23,505  make sure that the 'v4l2loopback' kernel module is installed and loaded
2021-09-11 10:38:23,505  or use the 'webcam=no' option
2021-09-11 10:38:23,505 found 0 virtual video devices for webcam forwarding

(Xpra:21107): Gtk-CRITICAL **: 10:38:23.613: gtk_widget_realize: assertion 'widget->priv->anchored || GTK_IS_INVISIBLE (widget)' failed
2021-09-11 10:38:23,887 waiting for initialization thread to complete
2021-09-11 10:38:23,890 xpra is ready.
2021-09-11 10:38:24,041 GStreamer version 1.14.4 for Python 3.7.3 64-bit
2021-09-11 10:38:24,146 xpra X11 seamless version 4.3-r867 64-bit
2021-09-11 10:38:24,147  uid=1001 (ged), gid=1001 (ged)
2021-09-11 10:38:24,147  running with pid 21107 on Linux Debian 10 buster
2021-09-11 10:38:24,183  connected to X11 display :103 with 24 bit colors
2021-09-11 10:38:27,749 loaded 82 start menu entries from 11 sub-menus in 4.3 seconds
2021-09-11 10:38:31,448 printer forwarding enabled using postscript and pdf
2021-09-11 10:38:31,456 started command '/etc/X11/Xsession true' with pid 21230
2021-09-11 10:38:31,505 3.7GB of system memory
2021-09-11 10:38:31,828 No OpenGL information available
2021-09-11 10:38:51,457 New unix-domain connection received
2021-09-11 10:38:51,457  on '/tmp/xpra/laptop3-103'
2021-09-11 10:38:51,465 Handshake complete; enabling connection
2021-09-11 10:38:51,486 Python/GTK3 Linux Raspbian 11 bullseye tty client version 4.3-r29977 32-bit
2021-09-11 10:38:51,486  OpenGL is disabled
2021-09-11 10:38:51,486  connected from 'piplus' as 'ged' - 'Ged'
2021-09-11 10:38:51,492 setting key repeat rate from client: 660ms delay / 40ms interval
2021-09-11 10:38:51,494 setting keymap: rules=evdev, model=pc105, layout=gb
2021-09-11 10:38:51,527 setting keyboard layout to 'gb'
2021-09-11 10:38:51,647  client root window size is 1600x900 with 1 display:
2021-09-11 10:38:51,647   :0.0 (423x238 mm - DPI: 96x96) workarea: 1600x879 
2021-09-11 10:38:52,152 server virtual display now set to 1600x900
2021-09-11 10:38:52,159  automatic picture encoding enabled, also available:
2021-09-11 10:38:52,159   png, png/P, png/L, rgb24, rgb32, jpeg, scroll
2021-09-11 10:38:52,193 DPI set to 96 x 96
2021-09-11 10:38:52,259 client   1 @05.922 Xpra X11 seamless server version 4.3-r867 64-bit
2021-09-11 10:38:52,261 client   1 @05.924  running on Linux Debian 10 buster
2021-09-11 10:38:52,302 client   1 @05.960 Attached to ssh://ged@laptop3/103
2021-09-11 10:38:52,303 client   1 @05.964  (press Control-C to detach)
2021-09-11 10:38:53,287 client   1 @06.949 running, 1 window
2021-09-11 10:38:54,690 client   1 @08.354 Error: cannot access the list of printers
2021-09-11 10:38:54,695 client   1 @08.357  module 'cups' has no attribute 'Connection'
2021-09-11 10:39:01,609 client   1 @15.271 Python/GTK3 Client got signal SIGINT
2021-09-11 10:39:01,610 client   1 @15.274 exiting
2021-09-11 10:39:01,614 client has requested disconnection: exit on signal SIGINT
2021-09-11 10:39:01,614 Disconnecting client /tmp/xpra/laptop3-103:
2021-09-11 10:39:01,615  client request
2021-09-11 10:39:01,617 xpra client 1 disconnected.
2021-09-11 10:39:14,887 New unix-domain connection received
2021-09-11 10:39:14,888  on '/tmp/xpra/laptop3-103'
2021-09-11 10:39:14,894 Handshake complete; enabling connection
2021-09-11 10:39:14,899 Python/GTK3 Linux Raspbian 11 bullseye tty client version 4.3-r29977 32-bit
2021-09-11 10:39:14,899  OpenGL is disabled
2021-09-11 10:39:14,899  connected from 'piplus' as 'ged' - 'Ged'
2021-09-11 10:39:14,901 setting key repeat rate from client: 660ms delay / 40ms interval
2021-09-11 10:39:14,903 keyboard mapping already configured (skipped)
2021-09-11 10:39:14,903  client root window size is 1600x900 with 1 display:
2021-09-11 10:39:14,904   :0.0 (423x238 mm - DPI: 96x96) workarea: 1600x879 
2021-09-11 10:39:14,905 best resolution matching 1600x900 is unchanged: 1600x900
2021-09-11 10:39:14,907  automatic picture encoding enabled, also available:
2021-09-11 10:39:14,907   png, png/P, png/L, rgb24, rgb32, jpeg, scroll
2021-09-11 10:39:15,014 client   2 @04.069 Xpra X11 seamless server version 4.3-r867 64-bit
2021-09-11 10:39:15,039 client   2 @04.073  running on Linux Debian 10 buster
2021-09-11 10:39:15,075 client   2 @04.137 Attached to ssh://ged@laptop3/103
2021-09-11 10:39:15,082 client   2 @04.138  (press Control-C to detach)
2021-09-11 10:39:16,038 client   2 @05.089 running, 1 window
2021-09-11 10:39:17,445 client   2 @06.507 Error: cannot access the list of printers
2021-09-11 10:39:17,453 client   2 @06.513  module 'cups' has no attribute 'Connection'
2021-09-11 10:39:21,099 client   2 @10.160 Python/GTK3 Client got signal SIGINT
2021-09-11 10:39:21,106 client   2 @10.168 exiting
2021-09-11 10:39:21,112 client has requested disconnection: exit on signal SIGINT
2021-09-11 10:39:21,112 Disconnecting client /tmp/xpra/laptop3-103:
2021-09-11 10:39:21,112  client request
2021-09-11 10:39:21,114 xpra client 2 disconnected.
2021-09-11 10:39:33,465 New unix-domain connection received
2021-09-11 10:39:33,465  on '/tmp/xpra/laptop3-103'
2021-09-11 10:39:33,468 Handshake complete; enabling connection
2021-09-11 10:39:33,473 Python/GTK3 Linux Raspbian 11 bullseye tty client version 4.3-r29977 32-bit
2021-09-11 10:39:33,473  OpenGL is disabled
2021-09-11 10:39:33,473  connected from 'piplus' as 'ged' - 'Ged'
2021-09-11 10:39:33,476 setting key repeat rate from client: 660ms delay / 40ms interval
2021-09-11 10:39:33,479 keyboard mapping already configured (skipped)
2021-09-11 10:39:33,479  client root window size is 1600x900 with 1 display:
2021-09-11 10:39:33,479   :0.0 (423x238 mm - DPI: 96x96) workarea: 1600x879 
2021-09-11 10:39:33,480 best resolution matching 1600x900 is unchanged: 1600x900
2021-09-11 10:39:33,484  automatic picture encoding enabled, also available:
2021-09-11 10:39:33,484   png, png/P, png/L, rgb24, rgb32, jpeg, scroll
2021-09-11 10:39:33,519 client   3 @04.031 Xpra X11 seamless server version 4.3-r867 64-bit
2021-09-11 10:39:33,606 client   3 @04.034  running on Linux Debian 10 buster
2021-09-11 10:39:33,666 client   3 @04.154 Attached to ssh://ged@laptop3/103
2021-09-11 10:39:33,673 client   3 @04.157  (press Control-C to detach)
2021-09-11 10:39:34,638 client   3 @05.151 running, 1 window
2021-09-11 10:39:36,022 client   3 @06.534 Error: cannot access the list of printers
2021-09-11 10:39:36,024 client   3 @06.536  module 'cups' has no attribute 'Connection'
2021-09-11 10:39:37,919 client   3 @08.434 Python/GTK3 Client got signal SIGINT
2021-09-11 10:39:37,922 client   3 @08.437 exiting
2021-09-11 10:39:37,925 client has requested disconnection: exit on signal SIGINT
2021-09-11 10:39:37,925 Disconnecting client /tmp/xpra/laptop3-103:
2021-09-11 10:39:37,925  client request
2021-09-11 10:39:37,927 xpra client 3 disconnected.
8<----------------------------------------------------------------------

Once again, thanks for xpra and for the help.

-- 

73,
Ged.