Re: no backlight on radeon after recent kernel "upgrade"s

From: Richard Purdie
Date: Wed Feb 21 2007 - 17:43:02 EST

On Wed, 2007-02-21 at 14:18 -0800, Alex Romosan wrote:
> Richard Purdie <rpurdie@xxxxxxxxx> writes:
> i have exactly the same problem with 2.6.21-rc1 on a thinkpad t40
> with an ati radeon card. the machine boots up but the backlight never
> comes on. 2.6.20 worked okay.

Can you have a look at the differences between the defconfigs for 2.6.20
and 2.6.21-rc1?

If the backlight changes are at fault, I'm guessing James' Kconfig
changes to the video Kconfig would be the culprit since
FB_RADEON_BACKLIGHT only used to be selectable if PMAC_BACKLIGHT was
enabled. On a thinkpad, the backlight is probably under ACPI control.

If FB_RADEON_BACKLIGHT wasn't set for 2.6.20, can you try 2.6.21-rc1
with that option disabled?

An ls /sys/class/backlight under 2.6.20 will tell us which driver it was



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