Logging in fails after update to latest kernel [4.2.0-39]

[mrcannibal]

Update 2 and solutions:

This problem isn't a bug after all. It's a feature. Since kernel 2.6.28, video modes are transferred to the kernel so that when you boot up, you can have pwetty graphics and splash screens and other unnecessary nonsense instead of the basic stuff that BIOS graphical modes allow. That works with open source generic drivers but there's a problem with proprietary ones.

Solution 1 (the non-solution): If you're not planning to do any gaming or any graphical-intense things on Linux with your graphics card, use the nouveau drivers and leave it at that.

Solution 2 (the sloppy emergency hack): This may lead to problems down the line so I wouldn't recommend it as a permanent solution. It's useful for fixing things, waiting until a fixed driver arrives or when you need to have your system back to do your work and don't have time to fiddle around with drivers and system innards.

Edit grub either with a CLI editor or by doing

sudo kate /etc/default/grub

and on the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

add nomodeset so that it becomes

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"

save the file and then do a grub update like this

sudo update-grub

And you're set.

More details about it: http://askubuntu.com/questions/20717...s-nomodeset-do and http://ubuntuforums.org/showthread.php?t=1613132

Solution 3 (installing the proper driver): The steps can be completed without any visible errors but it actually doesn't install the driver which I only realised when I tried to use something that utilises OpenGL.

This is the actual solution to the black screen problem but it's likely to break whenever the kernel is updated and might need to be repeated. I haven't gone through that process yet but I'd assume that you simply need to re-install the driver. The process here is pretty much the same as the tutorial here https://elementaryforums.com/index.p...lack-screen.7/ but I'm going to re-write the steps taken in case that forum becomes unavailable. Many thanks to the person who wrote that tutorial.

1. Go to www.nvidia.com and download the drivers for your specific card. Then go to the directory you saved them to and do this to make it executable

chmod +x NVIDIA_[I]whatever-version-you-downloaded[/I].run

2. Edit your grub in the manner shown in Solution 2, add nomodeset and a new line that looks like this

GRUB_GFXPAYLOAD_LINUX=XxY

substituting XxY with your resolution, for example GRUB_GFXPAYLOAD_LINUX=1366x768

upgrade grub after you're done

sudo update-grub

3. Find out what's your default display manager because you'll need to shut it down for a while, by doing this

cat /etc/X11/default-display-manager

In Kubuntu's 14.04 case it should be lightdm unless you switched from the default.

4. Go to a tty by pressing CTRL+ALT+F1 (press CTRL+ALT+F7 to return to a GUI for any reason).

Log in and then type this to stop the display manager

sudo /etc/init.d/lightdm stop

5. Find all nvidia packages on your system and remove them all in case they interfere with the installation of the new driver. Type

sudo dpkg --get-selections | grep nvidia

and you'll get the list of nvidia packages. Remove the ones labelled as "install", not the ones labelled "deinstall" by doing this

sudo apt-get autoremove [I]nvidia-304 nvidia-current nvidia-libopencl1-304  nvidia-libopencl1-331 nvidia-opencl-icd-304 nvidia-opencl-icd-331  nvidia-prime nvidia-settings[/I]

substitute the packages on the example above with whatever nvidia packages you have on your system. You can run dpkg --get-selections again to make sure that no nvidia packages have been left out.

6. Still in the tty, cd to the directory the nvidia drivers are and do

sudo ./NVIDIA_[I]whatever-version-you-downloaded[/I].run

At the pre-install script fail warning choose yes, 32-bit compatibility drivers choose yes, choose no if the installer offers you to add the configuration to your X configuration file.

At this point, you can remove nomodeset from your grub and update it. I don't think you should remove the other line with the resolution however so leave that in. Do all that and reboot and hopefully you'll have both a driver and you won't hit a black screen. For any missing details, refer to the original tutorial at the link above.

Solution 4 (alternative untested one): Tested it after all. Doesn't work.

Since the above requires manual updates of the driver, there might be a way to avoid doing that by adding the nvidia drivers ppa. Type

sudo add-apt-repository ppa:graphics-drivers/ppa

This will give you access to more up to date but more unstable drivers. I'm pretty sure you'll still need to put in the resolution line in grub and update it before anything works but I haven't tried that method myself.