[PATCH v2] backlight: propagate errors from get_brightness()

[Thomas Weißschuh]

On 2021-09-07T14:47+0200, Thomas Weißschuh wrote:
> backlight.h documents "struct backlight_ops->get_brightness()" to return
> a negative errno on failure.
> So far these errors have not been handled in the backlight core.
> This leads to negative values being exposed through sysfs although only
> positive values are documented to be reported.

> [..]

Friendly ping.