From 99fd28e19429f5212f0758adc1b2f08c6e63b6db Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Tue, 22 Mar 2011 16:30:27 -0700 Subject: [PATCH] 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: Matthew Garrett Acked-by: Richard Purdie Cc: Mourad De Clerck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/backlight/mbp_nvidia_bl.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/video/backlight/mbp_nvidia_bl.c b/drivers/video/backlight/mbp_nvidia_bl.c index b22cfb24bd55..dd0e145170b7 100644 --- a/drivers/video/backlight/mbp_nvidia_bl.c +++ b/drivers/video/backlight/mbp_nvidia_bl.c @@ -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;