startx cannot open /dev/fb0: Permission denied

Question

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?

Solution

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.

Comments

[Gilles 'SO- stop being evil']

It's a consequence of the recent change to rootless X (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).

[Magpie]

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?

[Cbhihe]

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.