Created attachment 128563 [details]
nouveau

The issue start to appear after upgrading to Kernel 4.9.0. Before that, on
4.8.14 everything seems to be fine.

I have Lenovo B560 laptop with Intel Core i5 560M and Iron Lake GPU, Nvidia
310M, so it's an Optimus laptop. I have external monitor connected to HDMI
port.

Components when the probelm could be reproduced:
- gentoo almost stable
- mesa 12.0.1 or 13.0.2;
- libdrm 2.4.68 or 2.4.73
- xorg 1.18.4 or 1.19.0
- intel xf86 driver snapshot or modesetting driver
- nouveau 1.0.12 or 1.0.13
- libinput 1.5.3, libevdev 1.5.2
- xfce, polkit, consolekit, dbus, etc.


So just after all services started and lightdm expected to appear with login
screen, instead I can only see console login screen and nothing appears on tty7
also.

Xorg.log.0 shows no errors, dmesg is also empy (even with debug level 4). I
can't reboot system after that as Xorg has red D symbol and cannot be killed,
so SysRq is used.

I blacklisted nouveau driver and it helped, so I can boot to the system
normally and after that I can load the nouveau module manually and even restart
Xorg.

Xorg.log.0 hangs on the following item:
[    14.361] (II) xfree86: Adding drm device (/dev/dri/card1)

syslog kernel with nouveau filtered (only one time I enabled debug level when
the I had the problem).