Screen flickers black after login

[someone]

Hi everyone!

I have installed Kubuntu 14.04 on my HP Elitebook 8540w as Dualboot with Windows. Grub version 0.97 as Bootloader.
The Laptop has a NVidia Quadro 1800M graphics card and i already installed the recommended NVidia driver version 340.

My problem is: if i boot with acpi not turned off i get the login-screen from KDE and if i enter the password and hit enter i get to the kde desktop but the screen starts to flicker black and after a few seconds the screen turns black and i get to the login-screen again. If i only work with the terminal (Ctrl+Alt+F1) it works stable, but as soon as i log into the graphical desktop, it doesn't work. If i turn acpi off at boot everything works fine.

I have already tried these options in /etc/default/grub:
acpi_osi=linux
acpi_backlight=vendor
noalpic
nouveau.blacklist=1

but they did not help with my problem.

[oshunluvr]

Might be something useful here:
http://www.linlap.com/hp_elitebook_8540w

Look through your logs (dmesg, syslog, Xorg.0.log) and see why or what is crashing.

[someone]

Thank you for the Link! It helped a lot and I found a "solution" for my problem there. If i turn PowerMizer in NVidia XServer on MaximumPerformance, i can switch on acpi and it works.

If i don't switch to MaximumPerformance, the dmesg log says:
[ 22.760534] nvidia: module license 'NVIDIA' taints kernel.
[ 22.760542] Disabling lock debugging due to kernel taint
[ 22.765828] nvidia: module verification failed: signature and/or required key missing - tainting kernel
...
[ 22.771921] NVRM: loading NVIDIA UNIX x86-64 Kernel Module 340.46 Wed Sep 24 14:23:40 PDT 2014
[ 23.224375] init: failsafe main process (718) killed by TERM signal
...
[ 23.914816] init: cups main process (816) killed by HUP signal
[ 23.914830] init: cups main process ended, respawning

...I think this is the interesting part which leads to the failure. I could not find anything suspicious.


For now i'm able to run it with MaximumPerformance. But i found another problem: with acpi turned on i cannot connect to an external monitor via VGA. I tried with Nvidia XServer and with xrandr to connect. The Xorg.0.log says:
[ 878.607] (II) NVIDIA(0): Setting mode "LVDS-0: nvidia-auto-select @1920x1080 +0+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0}"

but the display receives no signal. The display works fine if i turn off acpi on my laptop. Any ideas?

[oshunluvr]

So I'm clear: With acpi on the external monitor doesn't work. With acpi fully off (via bios) external monitor works.

In both modes (acpi on and off) boot up with vga connected and then post results of

xrandr -q

I suspect your ACPI just isn't fully supported and powerd might be turning off the vga port. You could try setting your power settings to "Desktop" mode just to check.

[someone]

I have tried xrandr -q. This are my results:

with acpi off:
Screen 0: minimum 8 x 8, current 3840 x 1080, maximum 8192 x 8192
VGA-0 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 509mm x 286mm
1920x1080 60.0*+
1680x1050 60.0
1600x900 60.0
1440x900 59.9
1280x1024 60.0
1280x720 60.0
1024x768 60.0
800x600 60.3
640x480 59.9
LVDS-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
1920x1080 60.0*+



with acpi on:
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 8192 x 8192
VGA-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
1920x1080 60.0*+ 40.0
LVDS-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
1920x1080 60.0*+ 40.0

after setting the correct position for VGA-0 (with acpi on):
Screen 0: minimum 8 x 8, current 3840 x 1080, maximum 8192 x 8192
VGA-0 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 344mm x 193mm
1920x1080 60.0*+ 40.0
LVDS-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
1920x1080 60.0*+ 40.0


(Sorry for the late reply!)

[oshunluvr]

Well, it appears that your bios/acpi is laying the VGA display on top of the LVDS display. Usually this would give you a mirrored display but for some reason, yours is overlaying the viewport. Weird.

Also strange: Your acpi is resizing your monitor:

with acpi off:
VGA-0 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 509mm x 286mm

with acpi on:
VGA-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm

This will totally screw with DPI and make it fuzzy. I think you may have to settle for running at Max Perf or figuring out the correct xrandr command(s) to get what you want.

[oshunluvr]

Any chance there's a bios update available for your machine?

[someone]

Thank you for your explanation of the xrandr output! I'm trying to get it the right way with some xrandr-commands.

I already run the latest bios version which is available for my laptop.