Login issue - nouveau error

[arindom]

While trying to log in to Kubuntu 15.04 (64-bit) via SDDM, I am getting the following error.

[ xx,xxxx] nouveau E[ PFIFO...... SCHED_ERROR [ UNK06 ]
[ xx,xxxx] nouveau E[ PFIFO...... SCHED_ERROR [ UNK06 ]
[ xx,xxxx] nouveau E[ PFIFO...... SCHED_ERROR [ UNK06 ]
....

This error continues to show till the login page appears. As soon as I enter the password in the Login UI, the whole system freezes, and no key functions. That means CTRL+F1 or CTRL+F2 doesn't work.

Here are the steps please :

1. Grub appears.
2. Selected Kubuntu 15.04.
3. Kubuntu logo appears.
4. The above error messages starts scrolling through.
5. It continues till the login manager appears.
6. Entered password.
7. System freezes.

Sometimes though, after several attempts I can get through to the Desktop. This issue started happened since the beta stage probably. Although I have installed 15.04 fresh from USB but the above issue persists.

Please also note that under Driver management software it shows "NVIDIA Corporation GK107M [GeForce GT 650M] and options to add drivers are showing as "...304.125, 340.76, 346.59 ..]. There is a checkbox for "Using Processor microcode firmware for Intel CPUs from Intel-microcode".

Need your help to get this issue resolved.

[Guest]

I had the same issue. My solution was to install the proprietary driver and blacklist the i915 module. I haven't tried anything with Nouveau yet.

[FONT=sans-serif]sudo apt-get install nvidia-346-updates[/FONT]
[FONT=sans-serif]vim /etc/modprobe.d/blacklist.conf[/FONT]

Add the following line:

[FONT=sans-serif]blacklist i915[/FONT]

Also, if you cannot get into the system (without it freezing) you can try appending "acpi=off noacpi nolapic nomodeset" in the Grub boot menu.

[arindom]

I had the same issue. My solution was to install the proprietary driver and blacklist the i915 module. I haven't tried anything with Nouveau yet.

[FONT=sans-serif]sudo apt-get install nvidia-346-updates[/FONT]
[FONT=sans-serif]vim /etc/modprobe.d/blacklist.conf[/FONT]

Add the following line:

[FONT=sans-serif]blacklist i915[/FONT]

Also, if you cannot get into the system (without it freezing) you can try appending "acpi=off noacpi nolapic nomodeset" in the Grub boot menu.

Thanks hekar for your help.

I tried the above but this time I got a black screen and SDDM was not appearing at all. So ultimately I have purged the nvidia drivers, removed the blacklist i915 statement and now I have been able to log in to the system. The default driver is showing as "Using X.org X Server - Nouveau driver ...".

Please also note that earlier I was able to successfully log in by changing the driver to "NVIDIA legacy binary driver - version 304.125 ..". It seems that for some reason in my system 346 is not working.