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: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index ae98990c7b66..bed58be1b205 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -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_clip_to_memory_range(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)
- *ppos += ret;
+ if (ret < 0)
+ return ret; /* return last error, if any */
+ else if (!ret)
+ return err; /* return previous error, if any */
- if (ret > 0)
- drm_fb_helper_damage(info, 0, 0, info->var.xres_virtual, info->var.yres_virtual);
+ *ppos += ret;
- return ret ? ret : err;
+ drm_fb_helper_clip_to_memory_range(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;
}
static void drm_fbdev_fb_fillrect(struct fb_info *info,
--
2.34.1
