Subject: Re: no backlight on radeon after recent kernel "upgrade"s
From: Richard Purdie <rpurdie@rpsys.net>
To: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: 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,
       James Simmons <jsimmons@infradead.org>
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Date: Thu, 22 Feb 2007 10:00:50 +0000
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On Wed, 2007-02-21 at 23:10 -0200, Henrique de Moraes Holschuh wrote:
> On Wed, 21 Feb 2007, Henrique de Moraes Holschuh wrote:
> > > * 'cat brightness' != 'cat actual_brightness' upon bootup (doesn't have
> > 
> > Hmm, I see this in 2.6.20 too.  And brightness is the one that is buggy.  I
> > will look into it.
> 
> Now, that was trivial to fix, and I will reply with a patch (which will have
> Cc's trimmed to just the MLs and Richard).
> 
> But really, should not the backlight *class* be doing the initial update of
> the brightness?  Looks like something that every device would need to do if
> the class doesn't do it, and unlike the "power it off on unregister" thing,
> I can't think of a reason not to do it for every backlight class device.
> 
> Please ACK the ibm-acpi patch in my next message if you'd like me to submit
> it to Len Brown for merging into 2.6.21, or NACK it if you'd rather do it in
> the backlight class core.

We can't change the backlight class code since some hardware can't read
from the device, only write to it. Initialisation in that case is a bit
different.

Richard


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