BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/568611 New acpi_brightness_hook_register lets another driver (e.g. i915) override the often-dysfunctional native acpi brightness control methods. Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx> --- drivers/acpi/video.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++---- include/acpi/video.h | 10 +++ 2 files changed, 147 insertions(+), 12 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index bd9843a..331fdcc 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -481,6 +481,12 @@ acpi_video_device_set_state(struct acpi_video_device *device, int state) return status; } +static unsigned int (*acpi_brightness_hook_routine) + (void *dev, unsigned int brightness) = NULL; +static char *acpi_brightness_hook_driver; +static void *acpi_brightness_hook_dev; +static unsigned int acpi_brightness_hook_max; + static int acpi_video_device_lcd_query_levels(struct acpi_video_device *device, union acpi_object **levels) @@ -520,13 +526,25 @@ acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level) struct acpi_object_list args = { 1, &arg0 }; int state; - arg0.integer.value = level; + /* If another driver has registered a brightness hook override, + * set the brightness using that method, otherwise set the brightness + * using the acpi _BCM method. */ + if ( acpi_brightness_hook_routine ) { + status = acpi_brightness_hook_routine(acpi_brightness_hook_dev, + level * acpi_brightness_hook_max / 100); + if ( status != 0 ) { + ACPI_ERROR((AE_INFO, "brightness hook failed")); + return -EIO; + } + } else { + arg0.integer.value = level; - status = acpi_evaluate_object(device->dev->handle, "_BCM", - &args, NULL); - if (ACPI_FAILURE(status)) { - ACPI_ERROR((AE_INFO, "Evaluating _BCM failed")); - return -EIO; + status = acpi_evaluate_object(device->dev->handle, "_BCM", + &args, NULL); + if (ACPI_FAILURE(status)) { + ACPI_ERROR((AE_INFO, "Evaluating _BCM failed")); + return -EIO; + } } device->brightness->curr = level; @@ -607,7 +625,10 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device, acpi_status status = AE_OK; int i; - if (device->cap._BQC || device->cap._BCQ) { + /* Try to get the current brightness using the _BQC/_BCQ method, only + * if another driver has not registered a brightness hook override. */ + if (!acpi_brightness_hook_routine + && (device->cap._BQC || device->cap._BCQ)) { char *buf = device->cap._BQC ? "_BQC" : "_BCQ"; status = acpi_evaluate_integer(device->dev->handle, buf, @@ -784,7 +805,7 @@ acpi_video_cmp_level(const void *a, const void *b) * device : video output device (LCD, CRT, ..) * * Return Value: - * Maximum brightness level + * 0 on success, error code on failure. * * Allocate and initialize device->brightness. */ @@ -944,6 +965,99 @@ out: * device : video output device (LCD, CRT, ..) * * Return Value: + * 0 on success, error code on failure. + * + * Allocate and initialize device->brightness. when a driver has registered + * a brightness hook override via acpi_brightness_hook_register. + * + * Cobbles up a fake brightness 'levels' array (emulating a _BCL list) and + * sets max brightness -- effectively what acpi_video_init_brightness does + * for the native acpi brightness methods + */ +static int +acpi_brightness_hook_init(struct acpi_video_device *device) +{ + struct acpi_video_device_brightness *br = NULL; + int result = -EINVAL; + int nsteps = 10; + int count, i; + static int initialized = 0; + + if ( initialized ) + return 1; + initialized = 1; + + device->brightness = NULL; + + br = kzalloc(sizeof(*br), GFP_KERNEL); + if (!br) { + printk(KERN_ERR "can't allocate memory\n"); + result = -ENOMEM; + return result; + } + br->levels = kmalloc((nsteps + 2) * sizeof *(br->levels), + GFP_KERNEL); + if (!br->levels) { + result = -ENOMEM; + kfree(br); + return result; + } + + for (count=2, i = 1; i <= nsteps; i++) + br->levels[count++] = (u32) i * 100 / nsteps; + br->levels[0] = 100; + br->levels[1] = br->levels[2+(nsteps/2)]; + br->count = count; + device->brightness = br; + + result = acpi_video_device_lcd_set_level(device, 100); + if (result) { + kfree(br->levels); + kfree(br); + device->brightness = NULL; + return result; + } + + /* Switch off acpi's native brightness switch control */ + brightness_switch_enabled = 0; + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "set up %d brightness levels\n", nsteps)); + + return 0; +} + +/* + * Arg: + * driver_name : name of the registering driver + * set_brightness_routine: pointer to the new set_brightness method + * dev : arbitrary pointer passed to set_brightness_routine + * max_brightness : set_brightnes_routines' maximum brightness value + * + * Return Value: + * None + * + * Register a brightness hook override method, which ACPI will use + * instead of its native _BCM/_BCL/_BQC methods. + */ +void acpi_brightness_hook_register( + char *driver_name, + unsigned int (*set_brightness_routine) + (void *dev, unsigned int brightness), + void *dev, int max_brightness) +{ + acpi_brightness_hook_routine = set_brightness_routine; + acpi_brightness_hook_driver = driver_name, + acpi_brightness_hook_dev = dev; + acpi_brightness_hook_max = max_brightness; +} +EXPORT_SYMBOL(acpi_brightness_hook_register); + +/* + * Arg: + * device : video output device (LCD, CRT, ..) + * + * Return Value: * None * * Find out all required AML methods defined under the output @@ -984,22 +1098,33 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device) device->cap._DSS = 1; } - if (acpi_video_backlight_support()) { + if (acpi_brightness_hook_routine || acpi_video_backlight_support()) { int result; static int count = 0; char *name; - result = acpi_video_init_brightness(device); + /* If another driver has registered a brightness hook override, + * call the brightness_hook init, otherwise call the native + * acpi_video brightness init. */ + if (acpi_brightness_hook_routine) + result = acpi_brightness_hook_init(device); + else + result = acpi_video_init_brightness(device); if (result) return; name = kzalloc(MAX_NAME_LEN, GFP_KERNEL); if (!name) return; - sprintf(name, "acpi_video%d", count++); + if (acpi_brightness_hook_routine) + sprintf(name, "%s", acpi_brightness_hook_driver); + else + sprintf(name, "acpi_video%d", count++); device->backlight = backlight_device_register(name, NULL, device, &acpi_backlight_ops); device->backlight->props.max_brightness = device->brightness->count-3; + dev_info(&device->dev->dev, + "registered as backlight/%s\n", name); kfree(name); result = sysfs_create_link(&device->backlight->dev.kobj, diff --git a/include/acpi/video.h b/include/acpi/video.h index cf7be3d..645b574 100644 --- a/include/acpi/video.h +++ b/include/acpi/video.h @@ -2,9 +2,19 @@ #define __ACPI_VIDEO_H #if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE) +extern void acpi_brightness_hook_register( + char *driver_name, + unsigned int (*set_brightness_routine) + (void *dev, unsigned int brightness), + void *dev, unsigned int max_brightness); extern int acpi_video_register(void); extern void acpi_video_unregister(void); #else +static inline acpi_brightness_hook_register( + char *driver_name, + unsigned int (*set_brightness_routine) + (void *dev, unsigned int brightness), + void *dev, unsigned int max_brightness) { return; } static inline int acpi_video_register(void) { return 0; } static inline void acpi_video_unregister(void) { return; } #endif -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
