11

When I try to start my WM using startx, I am unable to because the permission of something called /dev/fb0 are restricted.

From home/user/.local/share/xorg/Xorg.0.log:

[   198.569] (--) controlling tty is VT number 1, auto-enabling KeepTty
[   198.569] (II) Loading sub module "fbdevhw"
[   198.569] (II) LoadModule: "fbdevhw"
[   198.569] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[   198.570] (II) Module fbdevhw: vendor="X.Org Foundation"
[   198.570]    compiled for 1.16.0, module version = 0.0.2
[   198.570]    ABI class: X.Org Video Driver, version 18.0
[   198.570] (EE) open /dev/fb0: Permission denied
[   198.570] (WW) Falling back to old probe method for fbdev
[   198.570] (II) Loading sub module "fbdevhw"
[   198.570] (II) LoadModule: "fbdevhw"
[   198.570] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[   198.570] (II) Module fbdevhw: vendor="X.Org Foundation"
[   198.570]    compiled for 1.16.0, module version = 0.0.2
[   198.570]    ABI class: X.Org Video Driver, version 18.0
[   198.571] (EE) open /dev/fb0: Permission denied

Now of course I can change it using chmod, but I shouldn't have to do that every time I reboot the computer, so it seems like something is wrong / I haven't set up something properly.

What should I do to fix this?

Gilles 'SO- stop being evil'
  • 807,993
  • 194
  • 1,674
  • 2,175
Anonymous Entity
  • 345
  • 2
  • 4
  • 7
  • 4
    [It's a consequence of the recent change to rootless X](https://github.com/archlinuxarm/PKGBUILDs/issues/926) (i.e. the X server doesn't run as root any longer). Looks like rootless X is not ready for prime time on Arch. You can arrange to get the permission to access `/dev/fb0`, but you should not have to (if you google, you'll find recommendations to add yourself to the `video` group… but that's propping the armored door open, it defeats the purpose). – Gilles 'SO- stop being evil' Aug 13 '14 at 00:30

1 Answers1

13

Gilles is correct; this is due to the changes in xorg-server 1.16 which were announced on the Arch News.

To work around the permissions issue, you can use a Xorg.wrap config file to pass root rights, using:

needs_root_rights = yes

See man Xorg.wrap for the details.

You could also try using xf86-video-modesetting instead of xf86-video-fbdev until the fbdev driver is updated.

Community
  • 1
jasonwryan
  • 71,734
  • 34
  • 193
  • 226
  • 4
    I have this same problem with Fedora but this solution doesn't help I have `/etc/X11/Xwrapper.config` with `allowed_users=anybody` and `needs_root_rights=yes`. Any suggestions? – Magpie Jun 28 '15 at 11:18
  • I second @Magpie's comment, even though (not sure whether it matters) inserting a space before and after the "=" sign for each key-value pair in Xwrapper.config might help. In my case, having `needs_root_rights = yes` generates a few other errors, which weren't there to begin with, i.e. when only `(EE) open /dev/fb0: Permission denied` showed. – Cbhihe Sep 30 '18 at 11:21