[ltp] Re: speckles on t40 screen. dead pixels or drivers?

[Scott Jaderholm]

I think I might have found my problem. I ran memtest and it came up
with no errors, so it's not the system memory (although it reports
being 1Gb to windows and in hte IBM BIOS but it's really only 512mb, I
think). I found this on this page, and it seems to describe my problem
exactly. I guess I'll be talking with IBM on Monday.

http://bellet.info/laptop/t40.html

He says:

"Update 2003/08/10: I experienced a weird behaviour of my graphic card
since yesterday: a kind of screen corruption, that persisted even over
a cold reboot. I took some photos here, before the problem vanished as
silently as it appeared. On first cool reboot, the initial boot screen
was corrupted, like on this photo (look at the I and M letter), the
next GRUB screen was crippled too. Issueing a warn reboot with
CTRL-ALT-DEL caused a worse screen corruption : look at the ThinkPad
boot screen and the GRUB screen :-(. All 3D applications, like
FlightGear in this example, in 16bpp, were filled with white moving
dots and other image artifacts, like a dark translucent area moving
fast up and down over the 3D drawing area. The integrated PC-Doctor
diagnostic tool showed errors in the Video Adapter tests. Now all
tests pass fine again.


"This corruption disappeared in a second, while running Flightgear to
take the photo you saw above: the 3D image became clear again, and the
white dots disappeared. It showed up yesterday, while rebooting the
machine after a kernel crash. I also played flightgear yesterday
before the problem appeared, but I only noticed the damage at reboot.
So I have the feeling that this problem may be DRI-related, but that's
just my intuition. No errors in the XFree86 log. (my current radeon
driver settings are 24bpp, AGPMode "4", AgpFastWrite "off",
EnableDepthMoves "on", and EnablePageFlip "on").


"Update 2004/06/10: The screen corruption observed here happened again
last week. The machine got serviced, and the motherboard has been
replaced. The problem was related to bad video RAM. I have no idea on
what caused this damage. Kudos for the IBM technical service, that
repaired the laptop within two days !"


On Sun, 27 Mar 2005 01:17:58 -0500, Nate <nrs27@cornell.edu> wrote:
> I've never thought to do this, but if you have a perfectly working 
> monitor attached to a computer, take a screenshot, it will look fine. 
> But disconnect that monitor, plug in a monitor with glitches, take a 
> screenshot, shouldn't the screenshot itself look ok? If you follow this 
> logic, then I'd guess this is a driver problems, and not hardware.
> 
> >I took a screenshot of what it looks like and it's at
> >http://jaderholm.com/images/misc/lines.jpg.
> >
> >Any ideas guys?
> >
> >Sincerely,
> >Scott
> >  
> >
> 
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