TurboVNC, Xfce4, VirtualGL, and GLX

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1

Running a Xfce4 remote desktop through TurboVNC/3.0.1-GCCcore-11.3.0 and VirtualGL/3.0.2-GCCcore-11.3.0. This is from inside a Terminal app in remote desktop:

[w55c785@tempest-epyc003 ~]$ glxinfo
name of display: :1.0
Error: couldn’t find RGB GLX visual or fbconfig

From MobaXterm on my desktop, when I ssh -Y directly from the login node to tempest-epyc003:

[w55c785@tempest-epyc003 ~]$ glxinfo
name of display: localhost:10.0
display: localhost:10 screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.4
server glx extensions:
GLX_ARB_create_context, GLX_ARB_create_context_profile,
GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float,
GLX_ARB_framebuffer_sRGB, GLX_ARB_multisample,
GLX_EXT_create_context_es2_profile, GLX_EXT_fbconfig_packed_float,
GLX_EXT_framebuffer_sRGB, GLX_EXT_get_drawable_type,
GLX_EXT_import_context, GLX_EXT_visual_info, GLX_EXT_visual_rating,
GLX_MESA_copy_sub_buffer, GLX_OML_swap_method, GLX_SGIS_multisample,
GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group,
GLX_SGI_make_current_read, GLX_SGI_swap_control
client glx vendor string: Mesa Project and SGI

So the existing driver is being bound properly through ssh -Y but not when I start a remote desktop. For grins here is what is installed on all cpu nodes, so a driver is loaded:

sudo lspci -vv -s 62:00.0
62:00.0 VGA compatible controller: Matrox Electronics Systems Ltd. Integrated Matrox G200eW3 Graphics Controller (rev 04) (prog-if 00 [VGA controller])
DeviceName: Embedded Video
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- SERR- <PERR- INTx-
Latency: 0 (4000ns min, 8000ns max)
Interrupt: pin A routed to IRQ 259
NUMA node: 0
IOMMU group: 52
Region 0: Memory at de000000 (32-bit, prefetchable) [size=16M]
Region 1: Memory at e7808000 (32-bit, non-prefetchable) [size=16K]
Region 2: Memory at e7000000 (32-bit, non-prefetchable) [size=8M]
Expansion ROM at 000c0000 [virtual] [disabled] [size=128K]
Capabilities: [dc] Power Management version 3
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Kernel driver in use: mgag200
Kernel modules: mgag200

Without glx support I’m unable to get ParaView and VisIt working.

Any assistance would be much appreciated.

Kenny, MSU RCI

2

Hi Kenny.

Happy New Year and thanks for your post.

I’m just curious as to what happens if you open your terminal app as first described and run ssh -Y to that host. Not from the login server.

Using your same example with hostname tempest-epyc003

Get back to this point.

Running a Xfce4 remote desktop through TurboVNC/3.0.1-GCCcore-11.3.0 and VirtualGL/3.0.2-GCCcore-11.3.0. This is from inside a Terminal app in remote desktop:

and then run
ssh -Y tempest-epyc003 and then glxinfo.

Again, just curious as the results.

I did this experiment and I want to see what your results are in comparison to mine.

Thanks,
-gerald

3

Hi Gerald, Happy New Year to you too :slight_smile: Sure thing. Same results, except the DISPLAY variable now has localhost:10.0.

[w55c785@tempest-epyc010 ~]$ glxinfo

name of display: :1.0

Error: couldn’t find RGB GLX visual or fbconfig

[w55c785@tempest-epyc010 ~]$ ssh -Y tempest-epyc010

Activate the web console with: systemctl enable --now cockpit.socket

Last login: Fri Jan 6 14:35:09 2023

Welcome!

[w55c785@tempest-epyc010 ~]$ glxinfo

name of display: localhost:10.0

Error: couldn’t find RGB GLX visual or fbconfig

[w55c785@tempest-epyc010 ~]$

4

You’re DISPLAY (the environment variable) isn’t right. The command that failed, it said you’re on 1, but the output of your ssh session is 10.

When I get a desktop session I see a message like this. I just got DISPLAY 5.

Desktop 'TurboVNC: o0647.ten.osc.edu:5 (johrstrom)' started on display o0647.ten.osc.edu:5

It seems for whatever reason that environment variable isn’t being exported correctly OR that something else is setting it perhaps.

5

I don’t know what could be missing, I don’t set the DISPLAY variable. X11 and the display manager handle that. SSH negotiates for it with -X or -Y options. Everything in these scripts are the original files from your remote desktop github repository. Let me show you, I start up a new terminal in MobaXterm which handles (as you may well know) X11 forwarding:

 07/01/2023   16:00.28   /home/mobaxterm  echo $DISPLAY
127.0.0.1:0.0

 07/01/2023   16:00.32   /home/mobaxterm  ssh -Y tempest-login
Load key “/home/mobaxterm/.ssh/id_rsa”: invalid format
Activate the web console with: systemctl enable --now cockpit.socket

Last login: Sat Jan 7 16:00:02 2023 from 10.152.165.219
Welcome!
[w55c785@tempest-login ~]$ echo $DISPLAY
localhost:10.0
[w55c785@tempest-login ~]$

Notice the display is now :10.0. If you use ssh -v -Y you’ll see the ssh debug1 output which shows you the display negotiation. glxinfo does return a bunch of information regarding the capabilities of the Matrox driver installed.

VNC displays this at the top upon remote desktop launch, I can also verify it from output.log:
Desktop ‘TurboVNC: tempest-epyc002:1 (w55c785)’ started on display tempest-epyc002:1

There’s no such display as tempest-epyc002:1. Only :1.

[w55c785@tempest-epyc002 ~]$ glxinfo -display tempest-epyc002:1
Error: unable to open display tempest-epyc002:1

Here’s opening a Terminal straight away:

[w55c785@tempest-epyc002 ~]$ echo $DISPLAY
:1.0
[w55c785@tempest-epyc002 ~]$ glxinfo
name of display: :1.0
Error: couldn’t find RGB GLX visual or fbconfig

Out of curiosity, what does your glxinfo reveal about your display being set? I think it might boil down to configuration.

Kenny

6

job_script_content.sh is the one setting the DISPLAY. And we’re starting the script.sh (the one that actually boots the desktop) with that environment variable set.

[johrstrom f2cec55b-35af-4708-85d7-9b5ed54a865d()]  grep DISPLAY *.sh
job_script_content.sh:DISPLAY=:${display} "/users/PZS0714/johrstrom/ondemand/data/sys/dashboard/batch_connect/sys/bc_desktop/owens/output/f2cec55b-35af-4708-85d7-9b5ed54a865d/script.sh" &

What does the content of your output.log look like? Does it have any indication why this may be happening?

We seem to find the display through this grep expression.

display=$(echo "${VNC_OUT}" | awk -F':' '/^Desktop/{print $NF}')

Perhaps it’s not working for you?

7

Thanks, Jeff, I’ll dig through it. I’m in training all week so I’ll be slow to respond this week.

Kenny, MSU RCI

8

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