Commit fe23b56f authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

drm/fb-helper: Clip damage area to written memory range 



Write helpers used to mark the complete screen as dirty. This is
wasteful for writes that only change a small portion of the screen.
Fix the problem by computing the damaged area from the written
memory range and perform damage handling accordingly.

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209161617.3553-5-tzimmermann@suse.de
parent 67b723f5

drivers/gpu/drm/drm_fb_helper.c

+21 −7
Original line number Diff line number Diff line
@@ -754,11 +754,18 @@ EXPORT_SYMBOL(drm_fb_helper_sys_read); 
ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char __user *buf,

				size_t count, loff_t *ppos)

{

	loff_t pos = *ppos;

	ssize_t ret;

	struct drm_rect damage_area;



	ret = fb_sys_write(info, buf, count, ppos);

	if (ret > 0)

		drm_fb_helper_damage(info, 0, 0, info->var.xres, info->var.yres);

	if (ret <= 0)

		return ret;



	drm_fb_helper_memory_range_to_clip(info, pos, ret, &damage_area);

	drm_fb_helper_damage(info, damage_area.x1, damage_area.y1,

			     drm_rect_width(&damage_area),

			     drm_rect_height(&damage_area));



	return ret;

}
@@ -2237,6 +2244,7 @@ static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf, 
	loff_t pos = *ppos;

	size_t total_size;

	ssize_t ret;

	struct drm_rect damage_area;

	int err = 0;



	if (info->screen_size)
@@ -2265,13 +2273,19 @@ static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf, 
	else

		ret = fb_write_screen_buffer(info, buf, count, pos);



	if (ret > 0)

	if (ret < 0)

		return ret; /* return last error, if any */

	else if (!ret)

		return err; /* return previous error, if any */



	*ppos += ret;



	if (ret > 0)

		drm_fb_helper_damage(info, 0, 0, info->var.xres_virtual, info->var.yres_virtual);

	drm_fb_helper_memory_range_to_clip(info, pos, ret, &damage_area);

	drm_fb_helper_damage(info, damage_area.x1, damage_area.y1,

			     drm_rect_width(&damage_area),

			     drm_rect_height(&damage_area));



	return ret ? ret : err;

	return ret;

}



static void drm_fbdev_fb_fillrect(struct fb_info *info,