Bug#801655: xorg crashes with "NOUVEAU(0): failed to set mode: Permission denied" when exiting tty2-6 shell

[Sven Joachim <svenjoac@gmx.de>]

On 2015-10-13 05:13 +0200, Alexandre Hoïde wrote:

>    * What led up to the situation?
>    1. Boot to multi-user.target as [default] systemd target;
>    2. login to tty1 and 'startx' with following ~/.xsession :
>         xrdb -merge ~/.Xresources
>         exec /usr/bin/xmonad
>    3. switch and login to any of tty2-6 (CTRL-ALT-Fx), then 'exit' from
>    shell (bash) on this tty;
>    4. xorg crashes with :
> -----------------------------------------------------------------------
> […]
> [  6629.597] (II) AIGLX: Suspending AIGLX clients for VT switch
> [  6629.597] (II) NOUVEAU(0): NVLeaveVT is called.
> [  6629.783] (II) systemd-logind: got pause for 13:66
> […]
> [  6635.892] (II) systemd-logind: got resume for 226:0
> [  6636.046] (II) AIGLX: Resuming AIGLX clients after VT switch
> [  6636.046] (II) NOUVEAU(0): NVEnterVT is called.
> [  6636.047] (EE) NOUVEAU(0): failed to set mode: Permission denied
> [  6636.049] (EE) 
> Fatal server error:
> [  6636.049] (EE) EnterVT failed for screen 0
> [  6636.049] (EE) 
> [  6636.049] (EE) 
> […]
> [  6636.049] (EE) 
> [  6636.049] (II) AIGLX: Suspending AIGLX clients for VT switch
> [  6636.049] (II) NOUVEAU(0): NVLeaveVT is called.
> [  6636.059] (EE) Server terminated with error (1). Closing log file.
> -----------------------------------------------------------------------
>      
>    * Workaround :
>      - No such problem when launching 'startx' from any of tty2-6.
>      - No such problem with Gnome (residing on vt8, gdm vt7)
>
>    Sorry if this is not related to nouveau driver and regards,

I don't think this has anything to do with nouveau, rather I suspect the
X server which no longer runs suid root.  See bug #801518 for a similar
problem.

Anyway, you could try the modesetting driver, you would need this
minimal /etc/X11//etc/X11/xorg.conf to use it:

--8<---------------cut here---------------start------------->8---
Section "Device"
	Identifier	"n"
	Driver		"modesetting"
EndSection
--8<---------------cut here---------------end--------------->8---

Cheers,
       Sven