acpi: tie ACPI backlight devices to PCI devices if possible
Dual-GPU machines may provide more than one ACPI backlight interface. Tie
the backlight device to the GPU in order to allow userspace to identify
the correct interface.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Sedat Dilek <sedat.dilek@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index a9eec8c..a18e497 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -782,6 +782,9 @@
if (acpi_video_backlight_support()) {
struct backlight_properties props;
+ struct pci_dev *pdev;
+ acpi_handle acpi_parent;
+ struct device *parent = NULL;
int result;
static int count = 0;
char *name;
@@ -794,10 +797,20 @@
return;
count++;
+ acpi_get_parent(device->dev->handle, &acpi_parent);
+
+ pdev = acpi_get_pci_dev(acpi_parent);
+ if (pdev) {
+ parent = &pdev->dev;
+ pci_dev_put(pdev);
+ }
+
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_FIRMWARE;
props.max_brightness = device->brightness->count - 3;
- device->backlight = backlight_device_register(name, NULL, device,
+ device->backlight = backlight_device_register(name,
+ parent,
+ device,
&acpi_backlight_ops,
&props);
kfree(name);