[led-backlight] default-brightness-level issue

[Daniel Thompson]

On Fri, Apr 23, 2021 at 01:04:23PM +0000, pgeiem wrote:
> Dear all,
> 
> On a custom board I have a simple DPI panel. Panel's backlight is
> drive with an I2C led driver (PCA9632). led-backlight driver is sued
> to manage this as a backlight.
> 
> When using brightness-levels and default-brightness-level the
> backlight stay turned-off even if manually trying to set a different
> index value to brightness through sysfs.
> 
> I traced this issue as follow: When led_bl_update_status() is called
> the brightness value is returned from backlight_get_brightness() which
> call backlight_is_blank(). In my case backlight_is_blank() return true
> due to props.power = FB_BLANK_POWERDOWN which is != FB_BLANK_UNBLANK.
> 
> I traced why at startup props.power is FB_BLANK_POWERDOWN and found
> that in led_bl_probe() when a default brightness is set (>0)
> props.power is set to FB_BLANK_POWERDOWN which seems incorrect to me.
> 
> I made the small change below and default brightness is correctly used
> at startup.  I am not really sure this is an issue and if my change is
> correct or if I am doing something incorrect somewhere else. So I
> first would like to get your opinion on this and if correct will send
> a patch.

Makes sense. Please send this as a patch.


Daniel.