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When i press brightness key little faster the screen turns black(when graphic driver is not installed) or corrupted(when ati driver is used) and i have to forcefully restart again.This happens even with software brightness settings.I have to reduce brightness because brightness is set to maximum every time i logout/restart.

NOTE:I always use my laptop with ac adapter

Update: I have removed 12.04 and installed 13.04 and I faced same problem, I added "acpi_backlight=vendor" option and the brightness across the the sessions is saved. But the screen is still becoming garbled and forcing me to restart again, Here is the snapshot of my laptop screen.

Garbled screen forcing me force shut down

UPDATE: I have installed Manjaro Linux, to test for this problem, I have faced the same problem again. Seems like this a kernel level Problem.(I am pretty much screwed with any Linux Distro). Does anyone know a kernel, which does not have this problem. I will start testing out kernels from today.

I have tested many kernels in Ubuntu,Manjaro,Crunchbang. For me the only kernel which does not replicate the problem is 3.11.0. You can get the kernel from here. If anyone is facing the same problem and any other kernel is working, please share.

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Having the same issue on Dell Studio 1558 with AMD Radeon 5470. Hitting brightness keys causes the screen to go black (with open source driver) or fill with random colour pattern (fglrx).

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my card is also amd radeon5470.... – saiki4116 May 7 '12 at 10:38

It seems to work with acpi_backlight=vendor boot option.

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for brightness, that's working.but still the garbled screen persists – saiki4116 Aug 2 '13 at 18:31

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