Add a callback for drivers to provide framebuffer pages to fbdev's
deferred-I/O helpers. Implementations need to acquire a reference on
the page before returning it. Returning NULL generates a SIGBUS
signal.
This will be useful for DRM's fbdev emulation with GEM-shemem buffer
objects.
Signed-off-by: Thomas Zimmermann
---
drivers/video/fbdev/core/fb_defio.c | 4
include/linux/fb.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/drivers/video/fbdev/core/fb_defio.c
b/drivers/video/fbdev/core/fb_defio.c
index 6e0bbcfdb01b5..51928ff7961a5 100644
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -25,9 +25,13 @@
static struct page *fb_deferred_io_get_page(struct fb_info *info, unsigned
long offs)
{
+ struct fb_deferred_io *fbdefio = info->fbdefio;
const void *screen_buffer = info->screen_buffer;
struct page *page = NULL;
+ if (fbdefio->get_page)
+ return fbdefio->get_page(info, offs);
+
if (is_vmalloc_addr(screen_buffer + offs))
page = vmalloc_to_page(screen_buffer + offs);
else if (info->fix.smem_start)
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 708e6a177b1be..bbb0805c0ab1e 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -219,6 +219,7 @@ struct fb_deferred_io {
struct mutex lock; /* mutex that protects the pageref list */
struct list_head pagereflist; /* list of pagerefs for touched pages */
/* callback */
+ struct page *(*get_page)(struct fb_info *info, unsigned long offset);
void (*deferred_io)(struct fb_info *info, struct list_head *pagelist);
};
#endif
--
2.44.0
