Re: ACPI_VIDEO and BACKLIGHT_CLASS_DEVICE

Alan Stern
2010-11-12T03:00:06Z

On Fri, 12 Nov 2010, Zhang Rui wrote:

> On Thu, 2010-11-11 at 06:02 +0800, Alan Stern wrote:
> > Rui:
> >
> > Why does CONFIG_ACPI_VIDEO depend on BACKLIGHT_CLASS_DEVICE? Doesn't
> > ACPI_VIDEO apply to any sort of video adapter, including plain old VGA
> > adapters attached to a non-LCD device?
> >
> There is an ACPI device node (an ACPI video bus device) for the VGA
> controller and another ACPI device node (an ACPI video output device)
> for the LCD display.
> And ACPI_VIDEO knows how to switch the backlight of this integrated
> LCD. :)

But my computer doesn't have an LCD display. It's a desktop, not a
laptop. So why do I need BACKLIGHT_CLASS_DEVICE to be enabled?

Are you saying I don't need ACPI_VIDEO if the machine doesn't have an
integrated LCD display? That doesn't agree with the Kconfig help
message.

Alan Stern