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Date: Tue, 12 Jan 2010 17:28:33 +0000 (GMT)
From: James Simmons <jsimmons@infradead.org>
To: David John <davidjon@xenontk.org>
cc: Johan Hovold <jhovold@gmail.com>, Dave Airlie <airlied@redhat.com>,
       dri-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org,
       Eric Anholt <eric@anholt.net>, Jesse Barnes <jbarnes@virtuousgeek.org>
Subject: Re: [PATCH] drm/kms: fix fbdev blanking regression
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> On 01/07/2010 12:42 AM, Johan Hovold wrote:
> >> Yeap. The fix uncovered a bug in your driver. I haven't heard of problems 
> >> with the other drm drivers.
> >>  
> >>> The backlight is handled via the DRI driver I assume. At least
> >>> i9xx_crtc_dpms is called on powerdown.
> >>
> >> Can you post your dmesg and kernel config.
> 
> [snip]
> 
> Adding the Intel DRM people in CC as well. I have the same issue with my
> GM45.

Okay I looked at the code to figure out what is happening and why only 
this driver has problems. The problem is that the framebuffer layer 
expects the backlight to be a seperate device. The reason being is that
some embedded systems will use a gpio backlight. That way power management 
for a graphics card/backlight has 3 seperate states. Currently the intel 
DRM driver treats the backlight as being apart of the encoder. Jesse do 
you have objections to having the intel driver expose a backlight device.
The bonus of that is the user can also set the backlight levels.