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

[Rafael J. Wysocki]

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?

Rafael


> 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
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.