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Commit 99fd28e1 authored by Matthew Garrett's avatar Matthew Garrett Committed by Linus Torvalds
Browse files

mbp_nvidia_bl: check that the backlight control functions 



The SMI-based backlight control functionality may fail to work if the
system is running under EFI rather than BIOS.  Check that the hardware
responds as expected, and exit if it doesn't.

Signed-off-by: default avatarMatthew Garrett <mjg@redhat.com>
Acked-by: default avatarRichard Purdie <richard.purdie@linuxfoundation.org>
Cc: Mourad De Clerck <mourad@aquazul.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 23a9847f

drivers/video/backlight/mbp_nvidia_bl.c

+13 −0
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ static int __devinit mb_bl_add(struct acpi_device *dev) 
{

	struct backlight_properties props;

	struct pci_dev *host;

	int intensity;



	host = pci_get_bus_and_slot(0, 0);
@@ -163,6 +164,18 @@ static int __devinit mb_bl_add(struct acpi_device *dev) 
		return -ENODEV;

	}



	/* Check that the hardware responds - this may not work under EFI */



	intensity = hw_data->backlight_ops.get_brightness(NULL);



	if (!intensity) {

		hw_data->set_brightness(1);

		if (!hw_data->backlight_ops.get_brightness(NULL))

			return -ENODEV;



		hw_data->set_brightness(0);

	}



	if (!request_region(hw_data->iostart, hw_data->iolen,

			    "Macbook backlight"))

		return -ENXIO;