[ltp] ibm-acpi ThinkPad X60 brightness support problems

[Henrique de Moraes Holschuh]

Well, I have finally got down to try to track the bug with brightness in X60
ThinkPads.

And, well, whatever Lenovo did on the X60 that broke the brightness support,
it doesn't look like it was in the ACPI tables.  That means BIOS and/or EC
firmware, which is not something I am going to attempt to fix, unless
someone gives me a X60 as a gift ;-)

Therefore, we are stuck with properly identifying the bug, and then flooding
Lenovo with complains from X60 owners still under warranty, requesting a
fix.  I will add workarounds to ibm-acpi, if one is possible, but we don't
know much about that yet.

Obviously, I will need help from X60 owners as I cannot reproduce the
problem without a X60.

Problem description, as I understood it:

	1. Fn+Home/fn+End *do* work, but tpb, KDE and other similar
	"ThinkPad CMOS snooping" things don't report Fn+Home (brightness up)
	anymore.

	2. Lenovo changed the mappings and Fn+Home generates a hotkey event
	that is the same as the fn+F7 one (switch monitor output), which
	would explain all sort of weird behaviour if fn+F7 ain't safe in
	your particular configuration.

So, let's start with a few question for X60 owners with BIOS 2.x:

First, did I understood the problem correctly?  Do you have any extra
information on the issue?

Remember that if fn+Home is indeed causing fn+F7 events, something in your
system may well react to fn+F7 (and thus, also to fn+Home now), and, e.g.,
hang X *hard* trying to switch from the internal display to the external
output.  So have a look on the ThinkWiki pages about video output switching
before you report back any sort of weird behaviour that could be explained
by *that*.

Second, please set the ibm-acpi hotkey mask to 0xffff, and tell me what
events fn+Home, fn+End and fn+F7 are generating (probably it is safer to do
this from the console).

Third, please tell me if "echo 4 > /proc/acpi/ibm/cmos" (brightness up) and
"echo 5 > /proc/acpi/ibm/cmos" (brightness down) works.

Fourth, if you disable the bit for fn+F7 in the hotkey mask, what happens to
fn+F7 and fn+Home ? and if you enable it, what happens to fn+F7 an fn+Home?
(again, be careful if this would cause video output port switching, try it
from the console).

I am directing replies to this thread to the ibm-acpi-devel mailinglist.

-- 
  "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