From 7e3711eb87c584ed224a7ad7000eba36e6fa3a51 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 21 Mar 2025 10:53:55 +0100 Subject: fbdev: Track display blanking state Store the display's blank status in struct fb_info.blank and track it in fb_blank(). As an extra, the status is now available from the sysfs blank attribute. Support for blanking is optional. Therefore framebuffer_alloc() initializes the state to FB_BLANK_UNBLANK (i.e., the display is on). If the fb_blank callback has been set, register_framebuffer() sets the state to FB_BLANK_POWERDOWN. On the first modeset, the call to fb_blank() will update it to _UNBLANK. This is important, as listeners to FB_EVENT_BLANK will now see the display being switched on. Signed-off-by: Thomas Zimmermann Acked-by: Simona Vetter Link: https://lore.kernel.org/r/20250321095517.313713-3-tzimmermann@suse.de Signed-off-by: Lee Jones --- include/linux/fb.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/fb.h b/include/linux/fb.h index cd653862ab99..348aa2e146e2 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -472,6 +472,8 @@ struct fb_info { struct list_head modelist; /* mode list */ struct fb_videomode *mode; /* current mode */ + int blank; /* current blanking; see FB_BLANK_ constants */ + #if IS_ENABLED(CONFIG_FB_BACKLIGHT) /* assigned backlight device */ /* set before framebuffer registration, -- cgit v1.2.3 From 726491f2038ec71122d45700f3abf36fdb277aaa Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 21 Mar 2025 10:53:57 +0100 Subject: backlight: Implement fbdev tracking with blank state from event Look at the blank state provided by FB_EVENT_BLANK to determine whether to enable or disable a backlight. Remove the tracking fields from struct backlight_device. Tracking requires three variables, fb_on, prev_fb_on and the backlight's use_count. If fb_on is true, the display has been unblanked. The backlight needs to be enabled if the display was blanked before (i.e., prev_fb_on is false) or if use_count is still at 0. If fb_on is false, the display has been blanked. In this case, the backlight has to be disabled was unblanked before and the backlight's use_count is greater than 0. This change removes fbdev state tracking from blacklight. All the backlight requires it its own use counter and information about changes to the display. Removing fbdev internals makes backlight drivers easier to integrate into other display drivers, such as DRM. Signed-off-by: Thomas Zimmermann Reviewed-by: "Daniel Thompson (RISCstar)" Acked-by: Simona Vetter Link: https://lore.kernel.org/r/20250321095517.313713-5-tzimmermann@suse.de Signed-off-by: Lee Jones --- include/linux/backlight.h | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'include/linux') diff --git a/include/linux/backlight.h b/include/linux/backlight.h index f5652e5a9060..03723a5478f8 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -294,15 +294,7 @@ struct backlight_device { struct device dev; /** - * @fb_bl_on: The state of individual fbdev's. - * - * Multiple fbdev's may share one backlight device. The fb_bl_on - * records the state of the individual fbdev. - */ - bool fb_bl_on[FB_MAX]; - - /** - * @use_count: The number of uses of fb_bl_on. + * @use_count: The number of unblanked displays. */ int use_count; }; -- cgit v1.2.3 From b01beb2f1f6bcda17634a5b529865ffc5a9b795f Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 21 Mar 2025 10:53:59 +0100 Subject: backlight: Replace fb events with a dedicated function call Remove support for fb events from backlight subsystem. Provide the helper backlight_notify_blank_all() instead. Also export the existing helper backlight_notify_blank() to update a single backlight device. In fbdev, call either helper to inform the backlight subsystem of changes to a display's blank state. If the framebuffer device has a specific backlight, only update this one; otherwise update all. v4: - protect blacklight declarations with IS_REACHABLE() (kernel test robot) v3: - declare empty fb_bl_notify_blank() as static inline (kernel test robot) Signed-off-by: Thomas Zimmermann Acked-by: Simona Vetter Reviewed-by: "Daniel Thompson (RISCstar)" Link: https://lore.kernel.org/r/20250321095517.313713-7-tzimmermann@suse.de Signed-off-by: Lee Jones --- include/linux/backlight.h | 22 ++++++++++++++++------ include/linux/fb.h | 4 ++++ 2 files changed, 20 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/backlight.h b/include/linux/backlight.h index 03723a5478f8..10e626db7eee 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -12,7 +12,6 @@ #include #include #include -#include #include /** @@ -278,11 +277,6 @@ struct backlight_device { */ const struct backlight_ops *ops; - /** - * @fb_notif: The framebuffer notifier block - */ - struct notifier_block fb_notif; - /** * @entry: List entry of all registered backlight devices */ @@ -400,6 +394,22 @@ struct backlight_device *backlight_device_get_by_type(enum backlight_type type); int backlight_device_set_brightness(struct backlight_device *bd, unsigned long brightness); +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE) +void backlight_notify_blank(struct backlight_device *bd, + struct device *display_dev, + bool fb_on, bool prev_fb_on); +void backlight_notify_blank_all(struct device *display_dev, + bool fb_on, bool prev_fb_on); +#else +static inline void backlight_notify_blank(struct backlight_device *bd, + struct device *display_dev, + bool fb_on, bool prev_fb_on) +{ } +static inline void backlight_notify_blank_all(struct device *display_dev, + bool fb_on, bool prev_fb_on) +{ } +#endif + #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev) /** diff --git a/include/linux/fb.h b/include/linux/fb.h index 348aa2e146e2..835e13d6eba8 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -758,11 +758,15 @@ extern void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max) #if IS_ENABLED(CONFIG_FB_BACKLIGHT) struct backlight_device *fb_bl_device(struct fb_info *info); +void fb_bl_notify_blank(struct fb_info *info, int old_blank); #else static inline struct backlight_device *fb_bl_device(struct fb_info *info) { return NULL; } + +static inline void fb_bl_notify_blank(struct fb_info *info, int old_blank) +{ } #endif static inline struct lcd_device *fb_lcd_device(struct fb_info *info) -- cgit v1.2.3 From bc70cc84f5a2ebfd7e7112e9b8837e0c7954fc65 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 21 Mar 2025 10:54:01 +0100 Subject: backlight: lcd: Replace fb events with a dedicated function call Remove support for fb events from the lcd subsystem. Provide the helper lcd_notify_blank_all() instead. In fbdev, call lcd_notify_blank_all() to inform the lcd subsystem of changes to a display's blank state. Fbdev maintains a list of all installed notifiers. Instead of fbdev notifiers, maintain an internal list of lcd devices. v3: - export lcd_notify_mode_change_all() (kernel test robot) v2: - maintain global list of lcd devices - avoid IS_REACHABLE() in source file - use lock guards - initialize lcd list and list mutex Signed-off-by: Thomas Zimmermann Acked-by: Simona Vetter Reviewed-by: "Daniel Thompson (RISCstar)" Link: https://lore.kernel.org/r/20250321095517.313713-9-tzimmermann@suse.de Signed-off-by: Lee Jones --- include/linux/lcd.h | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/lcd.h b/include/linux/lcd.h index c3ccdff4519a..d4fa03722b72 100644 --- a/include/linux/lcd.h +++ b/include/linux/lcd.h @@ -11,7 +11,6 @@ #include #include -#include #define LCD_POWER_ON (0) #define LCD_POWER_REDUCED (1) // deprecated; don't use in new code @@ -79,8 +78,11 @@ struct lcd_device { const struct lcd_ops *ops; /* Serialise access to set_power method */ struct mutex update_lock; - /* The framebuffer notifier block */ - struct notifier_block fb_notif; + + /** + * @entry: List entry of all registered lcd devices + */ + struct list_head entry; struct device dev; }; @@ -125,6 +127,19 @@ extern void lcd_device_unregister(struct lcd_device *ld); extern void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld); +#if IS_REACHABLE(CONFIG_LCD_CLASS_DEVICE) +void lcd_notify_blank_all(struct device *display_dev, int power); +void lcd_notify_mode_change_all(struct device *display_dev, + unsigned int width, unsigned int height); +#else +static inline void lcd_notify_blank_all(struct device *display_dev, int power) +{} + +static inline void lcd_notify_mode_change_all(struct device *display_dev, + unsigned int width, unsigned int height) +{} +#endif + #define to_lcd_device(obj) container_of(obj, struct lcd_device, dev) static inline void * lcd_get_data(struct lcd_device *ld_dev) -- cgit v1.2.3 From dc2139c0aa3283e5749109641af1878ed7bf7371 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 21 Mar 2025 10:54:03 +0100 Subject: leds: backlight trigger: Replace fb events with a dedicated function call Remove support for fb events from the led backlight trigger. Provide the helper ledtrig_backlight_blank() instead. Call it from fbdev to inform the trigger of changes to a display's blank state. Fbdev maintains a list of all installed notifiers. Instead of the fbdev notifiers, maintain an internal list of led backlight triggers. v3: - export ledtrig_backlight_blank() v2: - maintain global list of led backlight triggers (Lee) - avoid IS_REACHABLE() in source file (Lee) - notify on changes to blank state instead of display state - use lock guards - initialize led list and list mutex Signed-off-by: Thomas Zimmermann Acked-by: Simona Vetter Link: https://lore.kernel.org/r/20250321095517.313713-11-tzimmermann@suse.de Signed-off-by: Lee Jones --- include/linux/leds.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux') diff --git a/include/linux/leds.h b/include/linux/leds.h index 98f9719c924c..b3f0aa081064 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -640,6 +640,12 @@ static inline void ledtrig_flash_ctrl(bool on) {} static inline void ledtrig_torch_ctrl(bool on) {} #endif +#if IS_REACHABLE(CONFIG_LEDS_TRIGGER_BACKLIGHT) +void ledtrig_backlight_blank(bool blank); +#else +static inline void ledtrig_backlight_blank(bool blank) {} +#endif + /* * Generic LED platform data for describing LED names and default triggers. */ -- cgit v1.2.3 From d32a0b567a8a8b6e677d35c4f8eb8bd32b7029a0 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 21 Mar 2025 10:54:04 +0100 Subject: fbdev: Remove constants of unused events The constants FB_EVENT_MODE_CHANGE and FB_EVENT_BLANK are unused. Remove them from the header file. Signed-off-by: Thomas Zimmermann Acked-by: Simona Vetter Link: https://lore.kernel.org/r/20250321095517.313713-12-tzimmermann@suse.de Signed-off-by: Lee Jones --- include/linux/fb.h | 6 ------ 1 file changed, 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/fb.h b/include/linux/fb.h index 835e13d6eba8..05cc251035da 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -129,18 +129,12 @@ struct fb_cursor_user { * Register/unregister for framebuffer events */ -/* The resolution of the passed in fb_info about to change */ -#define FB_EVENT_MODE_CHANGE 0x01 - #ifdef CONFIG_GUMSTIX_AM200EPD /* only used by mach-pxa/am200epd.c */ #define FB_EVENT_FB_REGISTERED 0x05 #define FB_EVENT_FB_UNREGISTERED 0x06 #endif -/* A display blank is requested */ -#define FB_EVENT_BLANK 0x09 - struct fb_event { struct fb_info *info; void *data; -- cgit v1.2.3