Subject: Re: [PATCH 2/2] ACPI Check for backlight support via ACPI video.ko otherwise use vendor ACPI drivers

From: Matthew Garrett <[email-masked]>
Date: Thu, 3 Jul 2008 23:29:27 +0100

On Thu, Jul 03, 2008 at 05:21:52PM +0100, Matthew Garrett wrote:
> On Thu, Jul 03, 2008 at 06:08:59PM +0200, Thomas Renninger wrote:
> 
> > +	if (ACPI_SUCCESS(acpi_get_handle(device->handle, "DRDY", &h_dummy))) {
> > +		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found IGD device\n"));
> > +		video_caps |= ACPI_VIDEO_IGD;
> > +	}
> 
> In principle, it's possible for a vendor to implement opregion but not 
> actually use it until the tche flags are set. If anyone's done that then 
> you've just broken backlight control on their system.

I've just had it confirmed that recent Panasonics behave this way. I 
suspect the same's true of many 965 systems.

-- 
Matthew Garrett | [email-masked]