Allow registered backlight drivers to receive a notification when a
backlight change is triggered via one of the siblings.
sony-laptop needs this notification to be able to set backlight when ALS
is enabled and setting brightness via _BCM becomes a no-op and only
notifies SNC that "a change to the brightness level" was requested
without giving any actual value.
Cc: Jingoo Han <jg1.han@xxxxxxxxxxx>
Signed-off-by: Mattia Dongili <malattia@xxxxxxxx>
---
drivers/video/backlight/backlight.c | 10 ++++++++++
include/linux/backlight.h | 3 +++
2 files changed, 13 insertions(+)
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 5d05555..0f9d6ce 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -88,6 +88,7 @@ static inline void backlight_unregister_fb(struct backlight_device *bd)
static void backlight_generate_event(struct backlight_device *bd,
enum backlight_update_reason reason)
{
+ struct backlight_device *obd;
char *envp[2];
switch (reason) {
@@ -104,6 +105,15 @@ static void backlight_generate_event(struct backlight_device *bd,
envp[1] = NULL;
kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
+
+ /* notify other bl devices */
+ list_for_each_entry(obd, &backlight_dev_list, entry) {
+ if (bd == obd || !obd->ops || !obd->ops->brightness_changed)
+ continue;
+
+ obd->ops->brightness_changed(obd, bd->props.brightness,
+ bd->props.max_brightness);
+ }
}
static ssize_t bl_power_show(struct device *dev, struct device_attribute *attr,
diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 5f9cd96..974ae3c 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -55,6 +55,9 @@ struct backlight_ops {
/* Check if given framebuffer device is the one bound to this backlight;
return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
int (*check_fb)(struct backlight_device *, struct fb_info *);
+ /* Callback to receive notification of a backlight change triggered by
+ a different backlight driver */
+ void (*brightness_changed)(struct backlight_device *, int, int);
};
/* This structure defines all the properties of a backlight */
--
1.9.0
--
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