Files
linux/drivers/video/fbdev/core/fb_info.c
Thomas Zimmermann 7e3711eb87 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 <tzimmermann@suse.de>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20250321095517.313713-3-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>
2025-04-10 10:38:57 +01:00

81 lines
1.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/export.h>
#include <linux/fb.h>
#include <linux/mutex.h>
#include <linux/slab.h>
/**
* framebuffer_alloc - creates a new frame buffer info structure
*
* @size: size of driver private data, can be zero
* @dev: pointer to the device for this fb, this can be NULL
*
* Creates a new frame buffer info structure. Also reserves @size bytes
* for driver private data (info->par). info->par (if any) will be
* aligned to sizeof(long). The new instances of struct fb_info and
* the driver private data are both cleared to zero.
*
* Returns the new structure, or NULL if an error occurred.
*
*/
struct fb_info *framebuffer_alloc(size_t size, struct device *dev)
{
#define BYTES_PER_LONG (BITS_PER_LONG/8)
#define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG))
int fb_info_size = sizeof(struct fb_info);
struct fb_info *info;
char *p;
if (size)
fb_info_size += PADDING;
p = kzalloc(fb_info_size + size, GFP_KERNEL);
if (!p)
return NULL;
info = (struct fb_info *) p;
if (size)
info->par = p + fb_info_size;
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);
#endif
return info;
#undef PADDING
#undef BYTES_PER_LONG
}
EXPORT_SYMBOL(framebuffer_alloc);
/**
* framebuffer_release - marks the structure available for freeing
*
* @info: frame buffer info structure
*
* Drop the reference count of the device embedded in the
* framebuffer info structure.
*
*/
void framebuffer_release(struct fb_info *info)
{
if (!info)
return;
if (WARN_ON(refcount_read(&info->count)))
return;
#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
mutex_destroy(&info->bl_curve_mutex);
#endif
kfree(info);
}
EXPORT_SYMBOL(framebuffer_release);