[Intel-gfx] [RFC] [intel-gfx] :The backlight issue when KMS is used
yakui.zhao at intel.com
Wed Apr 8 02:56:19 CEST 2009
On Tue, 2009-04-07 at 15:38 +0800, Matthew Garrett wrote:
> On Tue, Apr 07, 2009 at 03:25:23PM +0800, yakui_zhao wrote:
> > On Tue, 2009-04-07 at 13:57 +0800, Matthew Garrett wrote:
> > > No, since in UMS mode the X server handles the backlight registers.
> > If so, there is no change about the backlight flowchart in UMS mode.
> > And only when the KMS mode is used, a new backlight I/F is registered.
> > Right?
> > > The acpi case is uninteresting - acpi_video_backlight_support() doesn't
> > > require the acpi video driver. The platform driver case is more
> > > interesting, but the easiest solution is probably to add a notifier
> > > chain for backlight device add and have i915 unregister when a platform
> > > device registers.
> > Yes. We will have to create the communication channel between backlight
> > device and i915 driver. And when a backlight I/F is registered, we will
> > have to check whether the backlight I/F in 915 should be unregistered.
> > Right?
> > Does this make the problem complex?
> Not really. It's not a lot of code.
When a new backlight I/F is registered, it should unregister the
backlight I/F registered in 915 driver if it exists. And before i915
driver registers a backlight I/F, it will have to check whether the
backlight I/F is already registered by other code. If it exists, it will
And this code seems hack.
If so, we will have to do so even for the boxes based on non-intel
> > > I'm not sure what you mean by arbiter order?
> > What I said is which backlight I/F should be selected if there exist
> > multiple backlight I/F?
> The platform-specific one.
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