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authorMatthew Garrett <mjg@redhat.com>2011-03-22 16:30:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-22 17:44:00 -0700
commit99fd28e19429f5212f0758adc1b2f08c6e63b6db (patch)
tree9d9139fa58c28b1f8a40b77df7b839bc70c59a25 /drivers/video
parent23a9847f0d5252872c4fecb5d4f803c523bd9283 (diff)
downloadlinux-99fd28e19429f5212f0758adc1b2f08c6e63b6db.tar.bz2
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 <mjg@redhat.com> Acked-by: Richard Purdie <richard.purdie@linuxfoundation.org> Cc: Mourad De Clerck <mourad@aquazul.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/backlight/mbp_nvidia_bl.c13
1 files changed, 13 insertions, 0 deletions
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;