diff options
Diffstat (limited to 'drivers/acpi/video.c')
| -rw-r--r-- | drivers/acpi/video.c | 41 |
1 files changed, 35 insertions, 6 deletions
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 1bdfb37377e..a63566ba230 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -76,6 +76,7 @@ MODULE_LICENSE("GPL"); static int brightness_switch_enabled = 1; module_param(brightness_switch_enabled, 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); static int acpi_video_resume(struct acpi_device *device); @@ -2318,6 +2319,13 @@ static int __init intel_opregion_present(void) int acpi_video_register(void) { int result = 0; + if (register_count) { + /* + * if the function of acpi_video_register is already called, + * don't register the acpi_vide_bus again and return no error. + */ + return 0; + } acpi_video_dir = proc_mkdir(ACPI_VIDEO_CLASS, acpi_root_dir); if (!acpi_video_dir) @@ -2329,10 +2337,35 @@ int acpi_video_register(void) return -ENODEV; } + /* + * When the acpi_video_bus is loaded successfully, increase + * the counter reference. + */ + register_count = 1; + return 0; } EXPORT_SYMBOL(acpi_video_register); +void acpi_video_unregister(void) +{ + if (!register_count) { + /* + * If the acpi video bus is already unloaded, don't + * unload it again and return directly. + */ + return; + } + acpi_bus_unregister_driver(&acpi_video_bus); + + remove_proc_entry(ACPI_VIDEO_CLASS, acpi_root_dir); + + register_count = 0; + + return; +} +EXPORT_SYMBOL(acpi_video_unregister); + /* * This is kind of nasty. Hardware using Intel chipsets may require * the video opregion code to be run first in order to initialise @@ -2350,16 +2383,12 @@ static int __init acpi_video_init(void) return acpi_video_register(); } -void acpi_video_exit(void) +static void __exit acpi_video_exit(void) { - - acpi_bus_unregister_driver(&acpi_video_bus); - - remove_proc_entry(ACPI_VIDEO_CLASS, acpi_root_dir); + acpi_video_unregister(); return; } -EXPORT_SYMBOL(acpi_video_exit); module_init(acpi_video_init); module_exit(acpi_video_exit); |