[Intel-gfx] Legacy backlight control with KMS and BACKLIGHT property

[Zhenyu Wang]

On 2009.08.14 19:54:05 +0200, Matthias Hopf wrote:
> What we're supposing is
> 
> - a kernel driver for the /sys/class/backlight/ api for the legacy method

yeah, I think /sys/class/backlight/ should be the only backlight interface for 
any user space apps or X RandR property creation. So we need to add backlight
device inside i915 KMS driver, when !acpi_video_backlight_support().

Current KMS driver like LVDS only do PWM operation, maybe combo will be better
if it's supposed to be, Jesse?

> - support in the driver to actually open this one (trivial)

yeah.

> - support for the BACKLIGHT property in KMS case, *only* using the
>   kernel api method for now (will need some abstraction)

Current x-v-i driver in KMS could setup any property for all connectors,
like attached testing patch which will hook the property up. But if we just go 
with opening /sys/class/backlight/ in xorg driver, we simply don't need it...

So for X BACKLIGHT property creation, we'll have a checklist for acpi_video,
platform_driver, and new backlight device maybe like 'intel_lvds'.

-- 
Open Source Technology Center, Intel ltd.

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