Brightness Control not working on iMac12,2

hi all, got imac12,2 (27inch 813) yesterday , 64 bit installed fine under bootcamp mode (bios emulation), no brightness control.

searched forum bit, , lot of people under windows 7 x64 has same problem whereas windows 7 32bit works fine. went windows 7 32bit, again, brightness control not work under windows 7.

it's not issue of power because it's imac, it's screen bright hurts eyes, need take care of this.

it's videocard driver problem, unable find driver this, video card ati 6770m.

okay it's apple driver problem. uninstalled ati driver bootcamp package , brightness control works charm, except without proper video driver allow me run @ least @ system's native resolution.

please find ati standard driver install because other methods learned not work on latest 6770m video card.

in advance!

 

problem solved (partially)

there's 361 viewings of post , seems no 1 has answer.

fortunately lucky enough find temporary solution this.

i've heard people nvidia cards has same problem, specific problem, running following radeon driver:
radeon driver 8.812.0.0 dated jan 04, 2011 (seriously apple needs update this).

problem happens windows 7 x86 , x64 sp1 (not sure if it causing problem non-sp1 os).

solve problem, easiest way uninstall driver, , manually install again bootcamp driver package.

easy way remove driver using driver sweeper:
http://phyxion.net/item/driver-sweeper.html

after removed ati (now amd) driver completely, restart computer , find brightness works again, , navigate bootcamp driver folder (doesn't matter if 4.0 or 3.2 because driver version both bootcamp packages same). double click install driver , restart, , brightness control works again.

p.s. said bootcamp designated boot function cause problem, have yet test myself if happens case you, know do.

 

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