Hi
Am 20.02.24 um 10:17 schrieb Javier Martinez Canillas:
Thomas Zimmermann <tzimmermann@xxxxxxx> 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@xxxxxxx>
---
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 ?
bl_dev can only be used for display drivers that set an explicit
backlight device; otherwise it's NULL. There seem to be systems where
backlight and display are distinct. And the docs for check_fb say that
by default the backlight matches against any display. I tried to keep
this semantics by silently succeeding if neither check_fb nor bl_dev
have bene set.
The would be a driver bug, right ?
I assume that some systems create the backlight instance from platform
data or DT and the display driver has no means of knowing about it.
Best regards
Thomas
Regardless, the change makes sense to me.
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
