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-   -   LCD panel "blotching"...? (http://www.linuxquestions.org/questions/slackware-14/lcd-panel-blotching-4175489355/)

STDOUBT 12-27-2013 10:37 PM

LCD panel "blotching"...?
 
Installed Slackware 14.1 on a friends T60p (1680x1050) and all has gone
swimmingly! Very nice new version, seems slicker than ever (Full installation
sans KDE).

Only one hitch --
During the transition from the framebuffer to when "kernel mode setting"(?)
takes over the console (using runlevel3), there is a very brief yet somewhat
disturbing video effect I can only describe as a blotching. The screen is not
"garbled", but appears oversaturated, or out of range just for a second.
The effect does not even seem to involve the entire area of the screen
but the bulk of the center area. This same effect occurs on resume from
suspend just before the screensaver kicks on.

I have tried adding an xorg.conf with the radeon driver (same symptoms).
I tried setting "nomodesetting" in lilo.conf (same effect because KMS
kicks in).
I tried "video=1027x768" in lilo.conf, commenting "vga=791" (nope).


I'm just wondering if anyone has experienced this effect before and knows if
it a danger sign or how to get rid of it.
This laptop is new to us, and it is rather "old", so we don't know if this
is even normal. I don't imagine it should be. I'm worried this is bad for the
CCFL. This unit will cycle in and out of suspend several times per day...
Many thanks for any insights or advices!

EdGr 12-27-2013 11:54 PM

My Dell E1505 laptop does the same thing. I'm guessing that the momentary psychedelic colors are due to the LCD panel (not the back light) being power-cycled during the transition to KMS.

This doesn't appear to be a problem needing to be fixed.
Ed

STDOUBT 12-28-2013 03:15 AM

EdGr,
You're probably right. Out of curiosity, could you tell me the date/version of your BIOS?
It struck me that this issue may be related to an out of date BIOS vs. Xorg.
The T60p in question has a BIOS from 2007. I have another T60p in stock that
doesn't have this issue (running 14.0), BIOS dated 2011.

EdGr 12-28-2013 07:44 AM

The laptop was purchased in 2006. It has an Intel Core Duo T2500 processor, an ATI Mobility Radeon X1300 GPU, and a 1680x1050 LCD. This behavior appears to be caused by the Linux kernel's radeon driver. All of the KMS-enabled Slackware releases have shown the same momentary colors.
Ed

metaschima 12-28-2013 11:15 AM

I have seen this on old laptops with ATI cards as well. Like others have said, the radeon driver is likely the cause. You can report a bug if you like, maybe they'll fix it.


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