Re: [PATCH 01/10] backlight: Match backlight device against struct fb_info.bl_dev

Javier Martinez Canillas
2024-02-20T09:17:37Z

Thomas Zimmermann <tzimmermann@suse.de> writes:

Hello Thomas,

> Framebuffer drivers for devices with dedicated backlight are supposed
> to set struct fb_info.bl_dev to the backlight's respective device. Use
> the value to match backlight and framebuffer in the backlight core code.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
> drivers/video/backlight/backlight.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
> index 86e1cdc8e3697..48844a4f28ad3 100644
> --- a/drivers/video/backlight/backlight.c
> +++ b/drivers/video/backlight/backlight.c
> @@ -98,7 +98,8 @@ static int fb_notifier_callback(struct notifier_block *self,
> {
> struct backlight_device *bd;
> struct fb_event *evdata = data;
> - int node = evdata->info->node;
> + struct fb_info *info = evdata->info;
> + int node = info->node;
> int fb_blank = 0;
>
> /* If we aren't interested in this event, skip it immediately ... */
> @@ -110,8 +111,12 @@ static int fb_notifier_callback(struct notifier_block *self,
>
> if (!bd->ops)
> goto out;
> - if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))
> + else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
> goto out;
> +#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
> + else if (info->bl_dev && info->bl_dev != bd)

If the driver doesn't provide a struct backlight_ops .check_fb callback, I
think that having an info->bl_dev should be mandatory ? Or at least maybe
there should be a warning if info->bl_dev isn't set ?

The would be a driver bug, right ?

Regardless, the change makes sense to me.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

--
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat