[ltp] T60 white screen (internal LCD)

[Jan Kundrát]

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Hi,
last week, I used pressurized air to blow out the dust from the fan vent
of my T60 (2007-FRG). Unlike last time I did so, I did not turn the
machine off, so the fan was still running at its lowest speed. That was
a mistake, because since that time, the internal speed sensor won't work
(/proc/acpi/ibm/fan was saying speed: 0 all the time), and the fan run
essentially in full stop or full speed mode.

After I returned after a Saturday in nature (the machine was suspended
to RAM without electricity during that time), I simply opened the lid,
unlocked KDE4's kscreensaver, and started working (again just on
battery). After maybe five seconds, I saw a pretty impressive fade-out
effect where the internal LCD display went from its usual display into
an all-screen-is-white mode. I said "wtf" (I do not run any fancy
Compiz), connected the machine to its dock, pressed Fn+F7, which is
through the acpid hooked up to a xrandr script, activated the DVI
interface via that and continued working. After a few hours, I switched
the machine off. This is the part where it starts to get interesting, I
promise.

This morning, I removed the battery for a short while and put it back in
(to make the EC forget its worries), but each time the machine booted,
whether on AC or just on battery, the internal LCD would still remain
white. I can adjust the backlight via the function keys, but the real
contents is always 100% white. The good thing is that my fan regulation
is back -- right now, it indicates speed: 3064 and is pretty silent.
However, given the choice, I'd prefer a working LVDS output in
preference to a noisy fan :).

Summary:
- the fan regulation works again (just an EC soft-fail mode, I guess?)
- VGA-0 and DVI-0 work fine all the time (tested VGA in both X11 and
console, DVI-0 just in X11)
- LVDS (LCD) stays white in console and in X11; even the boot display
does not work

In addition to that, the integrated Bluetooth adapter "disappeared"
maybe an year ago (it just isn't visible from Linux, not even in
/proc/acpi/ibm). I'm adding this just for completeness, maybe it's
somehow an indication of a HW trouble.

Is there anything I can do to troubleshoot and/or fix the issue of
completely white internal LCD further, apart from visiting a service
center? I did try to search for a solution, but most cases deal with a
broken inverter, which should affect the backlight and not the displayed
contents, AFAIK.

With kind regards,
Jan

--=20
Trojita, a fast e-mail client -- http://trojita.flaska.net/


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