content of windows is not displayed

[A.]

Hi! After a recent update to Manjaro I started having problems when I start a vnc session: Login still works as always, but the content of some windows is not displayed. It works with e.g. Terminal window and Dolphin, but does not work with Thunderbird or Firefox. The error in journalctl when starting those is:

vncserver[713]: Could not map GPU buffer: Permission denied

Config is still the same:

session=plasma

securitytypes=vncauth,tlsvnc,plain

geometry=1920x1080

[Pierre Ossman]

On 24/04/2025 14:02, A. wrote:
> Hi! After a recent update to Manjaro I started having problems when I start
> a vnc session: Login still works as always, but the content of some windows
> is not displayed. It works with e.g. Terminal window and Dolphin, but does
> not work with Thunderbird or Firefox. The error in journalctl when starting
> those is:
>

> *vncserver[713]: Could not map GPU buffer: Permission denied*
>

Odd. What GPU is this?

What do the permissions on /dev/dri/render* look like?

Regards,
--
Pierre Ossman Software Development
Cendio AB https://cendio.com
Teknikringen 8 https://twitter.com/ThinLinc
583 30 Linköping https://facebook.com/ThinLinc
Phone: +46-13-214600

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

[A.]

Graphics card is Nvidia Quadro K420
NVIDIA-SMI 470.256.02   Driver Version: 470.256.02   CUDA Version: 11.4

As for /dev/dri/*
drwxr-xr-x   2 root root        100 by-path
crw-rw----+  1 root video  226,   0 card0
crw-rw----+  1 root video  226,   1 card1
crw-rw-rw-   1 root render 226, 128 renderD128

# file: dev/dri/by-path
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

# file: dev/dri/card0
# owner: root
# group: video
user::rw-
user:sddm:rw-
group::rw-
mask::rw-
other::---

# file: dev/dri/card1
# owner: root
# group: video
user::rw-
user:sddm:rw-
group::rw-
mask::rw-
other::---

# file: dev/dri/renderD128
# owner: root
# group: render
user::rw-
group::rw-
other::rw-

I added the user to both groups video and render.

[A.]

Using desktop session plasma

New 'prodesk:1 (<USERREMOVED>)' desktop is prodesk:1

Starting desktop session plasma

Xvnc TigerVNC 1.15.0 - built Feb 14 2025 19:55:10
Copyright (C) 1999-2025 TigerVNC team and many others (see README.rst)
See https://www.tigervnc.org for information on TigerVNC.
Underlying X server release 12101015

Thu Apr 24 15:08:41 2025
 vncext:      VNC extension running!
 vncext:      Listening for VNC connections on all interface(s), port 5901
 vncext:      Created VNC server for screen 0
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Could not resolve keysym XF86RefreshRateToggle
> Warning:          Could not resolve keysym XF86Accessibility
> Warning:          Could not resolve keysym XF86DoNotDisturb
Errors from xkbcomp are not fatal to the X server
[mi] mieq: warning: overriding existing handler (nil) with 0x560e323adce0 for event 2
[mi] mieq: warning: overriding existing handler (nil) with 0x560e323adce0 for event 3
xinit: XFree86_VT property unexpectedly has 0 items instead of 1
glx: failed to create dri3 screen
failed to load driver: nouveau
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Could not resolve keysym XF86RefreshRateToggle
> Warning:          Could not resolve keysym XF86Accessibility
> Warning:          Could not resolve keysym XF86DoNotDisturb
Errors from xkbcomp are not fatal to the X server

Thu Apr 24 15:08:55 2025
 Connections: Accepted: 192.168.0.1::50932
 SConnection: Client needs protocol version 3.8
 SConnection: Client requests security type VeNCrypt(19)
 SVeNCrypt:   Client requests security type VncAuth (2)

Thu Apr 24 15:08:58 2025
 VNCSConnST:  Server default pixel format depth 24 (32bpp) little-endian rgb888

Could not map GPU buffer: Permission denied

Could not map GPU buffer: Permission denied

Could not map GPU buffer: Permission denied

The permission denied line is repeated continuously after I open Firefox or Thunderbird and stops once I close the app. Checked a couple of other apps like Chromium and FileZilla and they work just fine. Only other app I found to show a blank window is Manjaros Add/Remove Software.

[Pierre Ossman]

On 24/04/2025 15:17, A. wrote:
> Graphics card is Nvidia Quadro K420
> NVIDIA-SMI 470.256.02 Driver Version: 470.256.02 CUDA Version: 11.4
>

I assume you are using Nvidia's proprietary driver, then?

In which case, this is expected:

> glx: failed to create dri3 screen
> failed to load driver: nouveau

But it is not expected that we see issues with applications like this.
Everything should be using CPU rendering at this point.

I'm afraid we don't have any Manjaro system here to test with. What you
can try is specify "renderNode=" in the settings, which should prevent
it even attempting to interface with the Nvidia driver.

Regards,
--
Pierre Ossman Software Development

Cendio AB http://cendio.com
Teknikringen 8 http://twitter.com/ThinLinc
583 30 Linköping http://facebook.com/ThinLinc

[A.]

I assume you are using Nvidia's proprietary driver, then?

Yes, the K420 is an older card and only the 470.xx driver branch still supports it. I've had less problems in general with the proprietary drivers than with nouveau, that's why I stick to those.

 

But it is not expected that we see issues with applications like this.
Everything should be using CPU rendering at this point.

I'm afraid we don't have any Manjaro system here to test with. What you
can try is specify "renderNode=" in the settings, which should prevent
it even attempting to interface with the Nvidia driver.

That's it, specifying rendernode= solved it! FF + TB + Add/Remove Software now display properly with no errors showing. Thanks, appreciate your help!