Subject: Re: no backlight on radeon after recent kernel "upgrade"s
From: Richard Purdie <rpurdie@rpsys.net>
To: Alex Romosan <romosan@sycorax.lbl.gov>
Cc: Yaroslav Halchenko <kernel@onerussian.com>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       linux-fbdev-devel@lists.sourceforge.net,
       James Simmons <jsimmons@infradead.org>
In-Reply-To: <877iub9mu2.fsf@sycorax.lbl.gov>
References: <20070219044616.GC25659@washoe.onerussian.com>
	 <20070219000412.acad13de.akpm@linux-foundation.org>
	 <1171876788.6046.3.camel@localhost.localdomain>
	 <877iub9mu2.fsf@sycorax.lbl.gov>
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Date: Wed, 21 Feb 2007 22:41:57 +0000
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On Wed, 2007-02-21 at 14:18 -0800, Alex Romosan wrote:
> Richard Purdie <rpurdie@rpsys.net> 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
using...

Thanks,

Richard


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