Comment 4 for bug 596641

I tried nvidia-bl without success...

I cannot install Bootcamp, and so cannot retrieve this MacHALDriver.sys file...
The work of disassembling may be useful as apple has released a patch related to the brightness handling for MacBook Pro 7,1 on windows [1].

If someone can provide MacHALDriver.sys from the latest bootcamp update, I can try to find the port, or perhaps, just ask Mario Schwalbe ;-)

[1] http://support.apple.com/kb/DL1044