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fbdev: mm: Deferred IO support

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This implements deferred IO support in fbdev.  Deferred IO is a way to delay
and repurpose IO.  This implementation is done using mm's page_mkwrite and
page_mkclean hooks in order to detect, delay and then rewrite IO.  This
functionality is used by hecubafb.

[adaplas]
This is useful for graphics hardware with no directly addressable/mappable
framebuffer. Implementing this will allow the "framebuffer" to be accesible
from user space via mmap().

Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jaya Kumar 2007-05-08 00:37:37 -07:00 • committed by Linus Torvalds
parent 3a2842480b
commit 60b59beafb
6 changed files with 239 additions and 0 deletions
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20
include/linux/fb.h
View file

@ -561,6 +561,16 @@ struct fb_pixmap {
void (*readio) (struct fb_info *info, void *dst, void __iomem *src, unsigned int size);
};
#ifdef CONFIG_FB_DEFERRED_IO
struct fb_deferred_io {
/* delay between mkwrite and deferred handler */
unsigned long delay;
struct mutex lock; /* mutex that protects the page list */
struct list_head pagelist; /* list of touched pages */
/* callback */
void (*deferred_io)(struct fb_info *info, struct list_head *pagelist);
};
#endif
/*
* Frame buffer operations
@ -778,6 +788,10 @@ struct fb_info {
struct mutex bl_curve_mutex;
u8 bl_curve[FB_BACKLIGHT_LEVELS];
#endif
#ifdef CONFIG_FB_DEFERRED_IO
struct delayed_work deferred_work;
struct fb_deferred_io *fbdefio;
#endif
struct fb_ops *fbops;
struct device *device; /* This is the parent */
@ -913,6 +927,12 @@ static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch,
}
}
#ifdef CONFIG_FB_DEFERRED_IO
/* drivers/video/fb_defio.c */
extern void fb_deferred_io_init(struct fb_info *info);
extern void fb_deferred_io_cleanup(struct fb_info *info);
#endif
/* drivers/video/fbsysfs.c */
extern struct fb_info *framebuffer_alloc(size_t size, struct device *dev);
extern void framebuffer_release(struct fb_info *info);