diff options
| author | Zhang Rui | 2009-12-30 15:59:23 +0800 |
|---|---|---|
| committer | Len Brown | 2009-12-30 20:30:04 -0500 |
| commit | c504f8cb68eb0d6cde53ba043daff8cb34586493 (patch) | |
| tree | 2d4500519867b0ff345c3e895d7fdb90739023a7 /drivers/acpi | |
| parent | 6b7b284958d47b77d06745b36bc7f36dab769d9b (diff) | |
ACPI video: Prune dupe video devices, unless "video.allow_duplicates"
Some buggy BIOS exports multiple ACPI video bus devices for the same
VGA controller, and multiple backlight control methods as well.
This messes up the ACPI video backlight control.
http://bugzilla.kernel.org/show_bug.cgi?id=13577
With this patch applied, only the FIRST ACPI video bus device
under a PCI device node is bind to ACPI video driver by default.
If the first ACPI video bus device doesn't work well, we can use
video.allow_duplicates=1 to go back to the old behavior.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/video.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 05dff631591c..45e6a29c8177 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -78,6 +78,13 @@ MODULE_LICENSE("GPL"); static int brightness_switch_enabled = 1; module_param(brightness_switch_enabled, bool, 0644); +/* + * By default, we don't allow duplicate ACPI video bus devices + * under the same VGA controller + */ +static int allow_duplicates; +module_param(allow_duplicates, bool, 0644); + static int register_count = 0; static int acpi_video_bus_add(struct acpi_device *device); static int acpi_video_bus_remove(struct acpi_device *device, int type); @@ -2233,11 +2240,47 @@ static int acpi_video_resume(struct acpi_device *device) return AE_OK; } +static acpi_status +acpi_video_bus_match(acpi_handle handle, u32 level, void *context, + void **return_value) +{ + struct acpi_device *device = context; + struct acpi_device *sibling; + int result; + + if (handle == device->handle) + return AE_CTRL_TERMINATE; + + result = acpi_bus_get_device(handle, &sibling); + if (result) + return AE_OK; + + if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME)) + return AE_ALREADY_EXISTS; + + return AE_OK; +} + static int acpi_video_bus_add(struct acpi_device *device) { struct acpi_video_bus *video; struct input_dev *input; int error; + acpi_status status; + + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, + device->parent->handle, 1, + acpi_video_bus_match, NULL, + device, NULL); + if (status == AE_ALREADY_EXISTS) { + printk(KERN_WARNING FW_BUG + "Duplicate ACPI video bus devices for the" + " same VGA controller, please try module " + "parameter \"video.allow_duplicates=1\"" + "if the current driver doesn't work.\n"); + if (!allow_duplicates) + return -ENODEV; + } video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL); if (!video) |