[Update][PATCH] ACPI / video / i915: Remove ACPI backlight if firmware expects Windows 8

[Igor Gnatenko]

On Wed, 2013-07-17 at 00:01 +0200, Rafael J. Wysocki wrote:
> On Tuesday, July 16, 2013 05:08:16 PM Matthew Garrett wrote:
> > On Tue, 2013-07-16 at 17:32 +0400, Igor Gnatenko wrote:
> > > Hmm. I found regression in user-space. In GNOME (maybe and other DEs) we no longer see switch status of backlight.
> > 
> > Yeah, I can duplicate that. Rafael, we have to call
> > acpi_video_init_brightness() even if we're not going to initialise the
> > backlight - Thinkpads seem to use this as the trigger for enabling ACPI
> > notifications rather than handling it in firmware. This seems to do the
> > job:
> 
> Igor, does this additional patch from Matthew help?
Yes. With this patch I have backlight switch indicator on my ThinkPad X230.
> 
> Rafael
> 
> 
Tested-by: Igor Gnatenko <i.gnatenko.brain at gmail.com>
> > diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
> > index 01b1a25..71865f7 100644
> > --- a/drivers/acpi/video.c
> > +++ b/drivers/acpi/video.c
> > @@ -900,6 +900,9 @@ static void acpi_video_device_find_cap(struct
> > acpi_video_device *device)
> >  		device->cap._DDC = 1;
> >  	}
> >  
> > +	if (acpi_video_init_brightness(device))
> > +		return;
> > +
> >  	if (acpi_video_verify_backlight_support()) {
> >  		struct backlight_properties props;
> >  		struct pci_dev *pdev;
> > @@ -909,9 +912,6 @@ static void acpi_video_device_find_cap(struct
> > acpi_video_device *device)
> >  		static int count = 0;
> >  		char *name;
> >  
> > -		result = acpi_video_init_brightness(device);
> > -		if (result)
> > -			return;
> >  		name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
> >  		if (!name)
> >  			return;
> > 
> > 
> > -- 
> > Matthew Garrett | mjg59 at srcf.ucam.org
> > 
-- 
Igor Gnatenko
Fedora release 19 (Schrödinger’s Cat)
Linux 3.11.0-0.rc0.git7.1.fc20.x86_64