diff options
Diffstat (limited to 'drivers/acpi/video_detect.c')
| -rw-r--r-- | drivers/acpi/video_detect.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index 815f75ef2411..2922f1f252d5 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -32,6 +32,7 @@ #include <linux/module.h> #include <linux/pci.h> #include <linux/types.h> +#include <linux/workqueue.h> #include <acpi/video.h> ACPI_MODULE_NAME("video"); @@ -41,6 +42,7 @@ void acpi_video_unregister_backlight(void); static bool backlight_notifier_registered; static struct notifier_block backlight_nb; +static struct work_struct backlight_notify_work; static enum acpi_backlight_type acpi_backlight_cmdline = acpi_backlight_undef; static enum acpi_backlight_type acpi_backlight_dmi = acpi_backlight_undef; @@ -262,6 +264,13 @@ static const struct dmi_system_id video_detect_dmi_table[] = { { }, }; +/* This uses a workqueue to avoid various locking ordering issues */ +static void acpi_video_backlight_notify_work(struct work_struct *work) +{ + if (acpi_video_get_backlight_type() != acpi_backlight_video) + acpi_video_unregister_backlight(); +} + static int acpi_video_backlight_notify(struct notifier_block *nb, unsigned long val, void *bd) { @@ -269,9 +278,8 @@ static int acpi_video_backlight_notify(struct notifier_block *nb, /* A raw bl registering may change video -> native */ if (backlight->props.type == BACKLIGHT_RAW && - val == BACKLIGHT_REGISTERED && - acpi_video_get_backlight_type() != acpi_backlight_video) - acpi_video_unregister_backlight(); + val == BACKLIGHT_REGISTERED) + schedule_work(&backlight_notify_work); return NOTIFY_OK; } @@ -304,6 +312,8 @@ enum acpi_backlight_type acpi_video_get_backlight_type(void) acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX, find_video, NULL, &video_caps, NULL); + INIT_WORK(&backlight_notify_work, + acpi_video_backlight_notify_work); backlight_nb.notifier_call = acpi_video_backlight_notify; backlight_nb.priority = 0; if (backlight_register_notifier(&backlight_nb) == 0) |