Bug#485465: battle for the brightness
On Thu, 26 Jun 2008, jidanni@jidanni.org wrote:
> HMH: be sure to add your warning to
> linux-doc-2.6.25/Documentation/laptops/thinkpad-acpi.txt.gz
There are warnings in there already, yes.
> And it seems the severity of this bug should be elevated: something on
> Debian is hijacking the brightness, causing the user to need to hit Fn
> End, or else go blind. But then we thus enter the realm of the user
Well, stop HAL. If the mess stops, at least we know it is something
dangling from HAL or DBUS.
> the same thing HMH warned about. If it could knock pixels out of "h"
> (like some kind of "melt" game), then it surely could blow holes into
> one's data (files) upon saving, etc. who knows -- and may be the root
> of all kinds of funny behavior.
I'd not go that far. It is likely to do crap in the GPU, which at most will
hard-hang your system. But even THAT would be a surprise, to date your
report is the first that speaks of anything more serious than the brightness
control just plain refusing to behave in an useful way.
> > Remove the ACPI video module from the system. See if that helps things.
> Maybe you mean one of these
> $ dlocate acpi|grep vid
> linux-image-2.6.25-2-686: /lib/modules/2.6.25-2-686/kernel/drivers/acpi/video.ko
> $ lsmod|grep acpi|grep v
> nvram 8396 1 thinkpad_acpi
> So I would need the exact command to proceed, if we are to explore
> this area still.
rmmod video
> > Compile thinkpad-acpi with the THINKPAD_ACPI_DEBUG Kconfig option, and
> > give the thinkpad-acpi module the parameter debug=0xffff. That might
> > produce some debug output I can use.
>
> Errgg... but I am just an apt-get kind of guy... that would be
> entering the deep part of the swimming pool for me.
Well, rmmod thinkpad-acpi; modprobe thinkpad-acpi debug=0xffff
will already help some (but not much).
> > Read the thinkpad-acpi docs in Documentation/thinkpad-acpi.txt (on the
> > kernel source tree) and play with the brightness_mode parameters, please.
> > Tell me what you find.
>
> Yes, I recall that I did want to try the brightness_mode parameter,
> but couldn't figure out how to use it. Apparently one needs to stick
You can unload thinkpad-acpi using "rmmod thinkpad-acpi", and then load it
back again with "modprobe thinkpad-acpi <parameters>".
> Anyway, this battle for the brightness seems to have started only a
> couple of months ago here on sid...
Which means it is probably crap in HAL.
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
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