pressing <Fn><F8> keys hangs emachines M6807
 

I installed 32 bit x86 linux 2.4.26-r6 on emachines M6807. Inside kde, pressing the <Fn><F8> keys to increase the brightness of the screen will hang the laptop.

My boot parameter in grub.conf file is:
pci=noacpi noapic

If these one or both two parameters are not used, same problem occurred.

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Edit:
Problem is solved by using 2.6.7-r11 kernel.