View Full Version : Dell 9400 LCD flicker and X lockup.

13th June 2007, 11:55 AM

I have had this issue with FC5, FC6 and FC7 and I have never found a solution, only work-arounds)

The best way to describe it is, the screen appears to flash bright white for a brief moment, it is very quick and not possible to really determine what happens.

Often it will lock X hard, such that ctrl-alt-backspace does not kill X. I am able to ssh to my laptop from another machine and do a shutdown, so it only seems that X has locked.

This seems to be an issue related to three things (anecdotal evidence would suggest):

1. Multi-core CPU OR just apic (not to be confused with acpi)
2. Nvidia drivers (not the nv driver)

I only see this issue with apic support turned on, that is, if I boot with kernel options noapic & nolapic then I have no issue. If I boot with apic enabled (FC7 requires option clocksource=acpi_pm to boot with apic support) flashy screen (at random).

Now, I suspect that it may be either the acpi or the dual cpu since with acpi disabled there is only 1 cpu available and /proc/cpu info only reports 1 cpu with 1 core, but no flashy screen.

I have never seen this issue with the nv dirver, but I want 3D support, so i'm stuck with dual cpu and flashy screen with random crashes or 1 core of the dual core cpu.

My hardware setup:

Dell 9400/E1705
nVidia Corporation GeForce Go 7900 GS (rev a1)
nvidia driver: 1.0.9762
CPU: Intel(R) Core(TM)2 CPU T7400 @ 2.16GHz

Very annoying, I would love to fix this issue.


28th June 2007, 11:24 AM
... No one else has this issue?

After some kernel upgrades, the acpi fixes are no longer required. But the same ol' issue still exists. That is the random flickers (varies from 10 min apart - 10sec apart) that sometimes locks X or something making X appear locked. But if I disable acpi with the noapic and nolapic boot options, the problem goes away, albeit with 1 cpu, 1 core..

No ideas?

8th July 2007, 07:01 PM
I have the same problem with a Dell XPS M1710, Core 2 T7200. The screen flashes then X locks up. Very annoying. I am running Fedora 7. Problem doesn't exist with nv driver. I really haven't been able to find out anything else about the problem, logs show nothing.

9th July 2007, 01:53 AM

Please if you ever solve this problem, please share it. I will certainly report anything I can find that will help.

I am currently stuck running with a single core so my machine is stable..


9th July 2007, 06:09 AM
I found this somewhere and tried it out, and I haven't seen any flashes or hangs since. In /etc/modprobe.d/nvidia, I changed this line
options NVreg_ModifyDeviceFiles=0 to this
options nvidia NVreg_RegistryDwords="PerfLevelSrc=0x2222" NVreg_Mobile=3 NVreg_ModifyDeviceFiles=0 Hope this helps.

10th July 2007, 10:10 AM

I'll give it a go. Thank you very much..

I'll report back if it fixes my issue also.


12th July 2007, 12:35 AM
OK, I've been running with this fix now for two days and no sign of issue.

Thankyou so much jrummy27....