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/fb.h') 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 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 --- drivers/video/backlight/backlight.c | 85 +++++---------------------------- drivers/video/fbdev/core/fb_backlight.c | 12 +++++ drivers/video/fbdev/core/fbmem.c | 2 + include/linux/backlight.h | 22 ++++++--- include/linux/fb.h | 4 ++ 5 files changed, 46 insertions(+), 79 deletions(-) (limited to 'include/linux/fb.h') diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index 1c43f579396f..9dc93c5e480b 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -15,7 +15,6 @@ #include #include #include -#include #include #ifdef CONFIG_PMAC_BACKLIGHT @@ -57,10 +56,10 @@ * a hot-key to adjust backlight, the driver must notify the backlight * core that brightness has changed using backlight_force_update(). * - * The backlight driver core receives notifications from fbdev and - * if the event is FB_EVENT_BLANK and if the value of blank, from the - * FBIOBLANK ioctrl, results in a change in the backlight state the - * update_status() operation is called. + * Display drives can control the backlight device's status using + * backlight_notify_blank() and backlight_notify_blank_all(). If this + * results in a change in the backlight state the functions call the + * update_status() operation. */ static struct list_head backlight_dev_list; @@ -78,11 +77,8 @@ static const char *const backlight_scale_types[] = { [BACKLIGHT_SCALE_NON_LINEAR] = "non-linear", }; -#if defined(CONFIG_FB_CORE) || (defined(CONFIG_FB_CORE_MODULE) && \ - defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) -static void backlight_notify_blank(struct backlight_device *bd, - struct device *display_dev, - bool fb_on, bool prev_fb_on) +void backlight_notify_blank(struct backlight_device *bd, struct device *display_dev, + bool fb_on, bool prev_fb_on) { guard(mutex)(&bd->ops_lock); @@ -103,68 +99,18 @@ static void backlight_notify_blank(struct backlight_device *bd, } } } +EXPORT_SYMBOL(backlight_notify_blank); -/* - * fb_notifier_callback - * - * This callback gets called when something important happens inside a - * framebuffer driver. The backlight core only cares about FB_BLANK_UNBLANK - * which is reported to the driver using backlight_update_status() - * as a state change. - * - * There may be several fbdev's connected to the backlight device, - * in which case they are kept track of. A state change is only reported - * if there is a change in backlight for the specified fbdev. - */ -static int fb_notifier_callback(struct notifier_block *self, - unsigned long event, void *data) +void backlight_notify_blank_all(struct device *display_dev, bool fb_on, bool prev_fb_on) { struct backlight_device *bd; - struct fb_event *evdata = data; - struct fb_info *info = evdata->info; - const int *fb_blank = evdata->data; - struct backlight_device *fb_bd = fb_bl_device(info); - bool fb_on, prev_fb_on; - - /* If we aren't interested in this event, skip it immediately ... */ - if (event != FB_EVENT_BLANK) - return 0; - - bd = container_of(self, struct backlight_device, fb_notif); - - if (fb_bd && fb_bd != bd) - return 0; - - fb_on = fb_blank[0] == FB_BLANK_UNBLANK; - prev_fb_on = fb_blank[1] == FB_BLANK_UNBLANK; - - backlight_notify_blank(bd, info->device, fb_on, prev_fb_on); - - return 0; -} - -static int backlight_register_fb(struct backlight_device *bd) -{ - memset(&bd->fb_notif, 0, sizeof(bd->fb_notif)); - bd->fb_notif.notifier_call = fb_notifier_callback; - return fb_register_client(&bd->fb_notif); -} + guard(mutex)(&backlight_dev_list_mutex); -static void backlight_unregister_fb(struct backlight_device *bd) -{ - fb_unregister_client(&bd->fb_notif); -} -#else -static inline int backlight_register_fb(struct backlight_device *bd) -{ - return 0; + list_for_each_entry(bd, &backlight_dev_list, entry) + backlight_notify_blank(bd, display_dev, fb_on, prev_fb_on); } - -static inline void backlight_unregister_fb(struct backlight_device *bd) -{ -} -#endif /* CONFIG_FB_CORE */ +EXPORT_SYMBOL(backlight_notify_blank_all); static void backlight_generate_event(struct backlight_device *bd, enum backlight_update_reason reason) @@ -455,12 +401,6 @@ struct backlight_device *backlight_device_register(const char *name, return ERR_PTR(rc); } - rc = backlight_register_fb(new_bd); - if (rc) { - device_unregister(&new_bd->dev); - return ERR_PTR(rc); - } - new_bd->ops = ops; #ifdef CONFIG_PMAC_BACKLIGHT @@ -547,7 +487,6 @@ void backlight_device_unregister(struct backlight_device *bd) bd->ops = NULL; mutex_unlock(&bd->ops_lock); - backlight_unregister_fb(bd); device_unregister(&bd->dev); } EXPORT_SYMBOL(backlight_device_unregister); diff --git a/drivers/video/fbdev/core/fb_backlight.c b/drivers/video/fbdev/core/fb_backlight.c index 6fdaa9f81be9..dbed9696f4c5 100644 --- a/drivers/video/fbdev/core/fb_backlight.c +++ b/drivers/video/fbdev/core/fb_backlight.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0-or-later +#include #include #include #include @@ -36,4 +37,15 @@ struct backlight_device *fb_bl_device(struct fb_info *info) return info->bl_dev; } EXPORT_SYMBOL(fb_bl_device); + +void fb_bl_notify_blank(struct fb_info *info, int old_blank) +{ + bool on = info->blank == FB_BLANK_UNBLANK; + bool prev_on = old_blank == FB_BLANK_UNBLANK; + + if (info->bl_dev) + backlight_notify_blank(info->bl_dev, info->device, on, prev_on); + else + backlight_notify_blank_all(info->device, on, prev_on); +} #endif diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 9650b641d8e8..c931f270ac34 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -363,6 +363,8 @@ int fb_blank(struct fb_info *info, int blank) if (ret) goto err; + fb_bl_notify_blank(info, old_blank); + fb_notifier_call_chain(FB_EVENT_BLANK, &event); return 0; 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 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/fb.h') 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