On 2/6/22 20:29, Thomas Zimmermann wrote:
> 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>
> ---
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
> 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;
> +
I also like how you cleaned up the error checking here and below
to just return early, instead of checking if ret > 0 to perform
the damage handling.
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
