Commit 7e3711eb authored by Thomas Zimmermann's avatar Thomas Zimmermann Committed by Lee Jones
Browse files

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: default avatarThomas Zimmermann <tzimmermann@suse.de>
Acked-by: default avatarSimona Vetter <simona.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20250321095517.313713-3-tzimmermann@suse.de


Signed-off-by: default avatarLee Jones <lee@kernel.org>
parent 93e41f96

drivers/video/fbdev/core/fb_info.c

+1 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ struct fb_info *framebuffer_alloc(size_t size, struct device *dev) 


	info->device = dev;

	info->fbcon_rotate_hint = -1;

	info->blank = FB_BLANK_UNBLANK;



#if IS_ENABLED(CONFIG_FB_BACKLIGHT)

	mutex_init(&info->bl_curve_mutex);

drivers/video/fbdev/core/fbmem.c

+16 −1
Original line number Diff line number Diff line
@@ -341,6 +341,7 @@ EXPORT_SYMBOL(fb_set_var); 


int fb_blank(struct fb_info *info, int blank)

{

	int old_blank = info->blank;

	struct fb_event event;

	int ret;
@@ -353,13 +354,19 @@ int fb_blank(struct fb_info *info, int blank) 
	event.info = info;

	event.data = &blank;



	info->blank = blank;



	ret = info->fbops->fb_blank(blank, info);

	if (ret)

		return ret;

		goto err;



	fb_notifier_call_chain(FB_EVENT_BLANK, &event);



	return 0;



err:

	info->blank = old_blank;

	return ret;

}

EXPORT_SYMBOL(fb_blank);
@@ -408,6 +415,14 @@ static int do_register_framebuffer(struct fb_info *fb_info) 
	mutex_init(&fb_info->lock);

	mutex_init(&fb_info->mm_lock);



	/*

	 * With an fb_blank callback present, we assume that the

	 * display is blank, so that fb_blank() enables it on the

	 * first modeset.

	 */

	if (fb_info->fbops->fb_blank)

		fb_info->blank = FB_BLANK_POWERDOWN;



	fb_device_create(fb_info);



	if (fb_info->pixmap.addr == NULL) {

drivers/video/fbdev/core/fbsysfs.c

+4 −4
Original line number Diff line number Diff line
@@ -242,11 +242,11 @@ static ssize_t store_blank(struct device *device, 
	return count;

}



static ssize_t show_blank(struct device *device,

			  struct device_attribute *attr, char *buf)

static ssize_t show_blank(struct device *device, struct device_attribute *attr, char *buf)

{

//	struct fb_info *fb_info = dev_get_drvdata(device);

	return 0;

	struct fb_info *fb_info = dev_get_drvdata(device);



	return sysfs_emit(buf, "%d\n", fb_info->blank);

}



static ssize_t store_console(struct device *device,

include/linux/fb.h

+2 −0
Original line number Diff line number Diff line
@@ -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,