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

From: James Simmons <jsimmons@infradead.org>
To: Richard Purdie <rpurdie@rpsys.net>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
	Alex Romosan <romosan@sycorax.lbl.gov>,
	Yaroslav Halchenko <kernel@onerussian.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,
	linux-fbdev-devel@lists.sourceforge.net
Subject: Re: no backlight on radeon after recent kernel "upgrade"s
Date: Thu, 22 Feb 2007 16:00:16 +0000 (GMT)	[thread overview]
Message-ID: <Pine.LNX.4.64.0702221558550.29542@pentafluge.infradead.org> (raw)
In-Reply-To: <1172157592.5837.89.camel@localhost.localdomain>

> > Howerver, I *do* strongly wish for a way to combine various drivers into a
> > single backlight device, where radeon/intelfb takes care of some stuff,
> > ibm-acpi/asus-laptop/sony-laptop takes care of other stuff, etc.  Also, a
> > standard naming for the builtin screen(s) would help, calling it "ibm",
> > "asus", "sony" is not good IMHO.
> 
> I wasn't aware of this problem. If some devices need bits from both
> raedon/whatever and acpi, the current implementations are just plain
> wrong. Its not really a backlight class problem and more of an
> implementation and interaction problem between acpi and the framebuffer
> drivers. They should be presenting and registering *one* backlight class
> device, not two. Without knowing more about the circumstances and
> how/when to combine which drivers its hard for me to help further...

This is always been a problem. For the fbdev layer you can run vesafb with 
a specific fbdev driver and they both access the same hardware. There is 
no really way around this. The user has to be smart enough to not enable 
bothe drivers.