[Intel-gfx] RFC] [Patch] [DRM/I915] :Check the LID device to decide whether the LVDS should be initialized

[Jesse Barnes]

On Thu, 11 Jun 2009 18:03:34 +0800
yakui_zhao <yakui.zhao at intel.com> wrote:

> Hi, All
> 
>     This is a patch that the LID device is checked to decide whether
> the LVDS should be initialized. If there is no LID device, it won't
> initialize the LVDS output device in KMS mode on the boxes based on
> intel mobile chipset. In such case the pipe occupied by LVDS can be
> used for other output device. If the LID device can be found, it will
> continue the current flowchart. 
>     On some boxes the mobile chipset is used and there is no LVDS
> device. In such case we had better not initialize the LVDS output
> device so that one pipe can be used for other output device. For
> example: E-TOP in bug 21496
> 
> But unfortunately the LVDS device is still initialized on such boxes
> based on mobile chipset in KMS mode. It brings that this pipe
> occupied by LVDS can't be used for other output device.
> 
> After checking the acpidump we find that there is no LID device on
> such boxes. In such case we can use the LID device to decide whether
> the LVDS device should be initialized. 
> 
> If there is no LID device, we can think that there is no LVDS device.
> It is unnecessary to initialize the LVDS output device.
> If there exists the LID device, it will continue the current
> flowchart.
> 
> Maybe on some boxes there is no LVDS device but the LID device is
> found. In such case it had better be added to the quirk table.

Sounds like a reasonable heuristic (along the lines of checking for
battery support like Michael suggested).  I'll let ACPI hackers comment
on the code...

Jesse

-- 
Jesse Barnes, Intel Open Source Technology Center