On Tue, Oct 13, 2020 at 01:01:02AM -0700, Alexandru Stan wrote:
> After the "PWM backlight interpolation adjustments" patches, the
> backlight interpolation works a little differently. The way these
> dts files were working before was relying on a bug (IMHO).
>
> Remove the 0-3 range since otherwise we would have a 252 long
> interpolation that would slowly go between 0 and 3, looking really bad
> in userspace.
>
> We don't need the 0% point, userspace seems to handle this just fine
> because it uses the bl_power property to turn off the display.
>
> Signed-off-by: Alexandru Stan <amstan@xxxxxxxxxxxx>
Acked-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Note also shouldn't this be patch 1 of the set. AFAICT it makes sense
whether or not the interpolation algorithm is changed.
Daniel.
> ---
>
> arch/arm/boot/dts/rk3288-veyron-jaq.dts | 2 +-
> arch/arm/boot/dts/rk3288-veyron-minnie.dts | 2 +-
> arch/arm/boot/dts/rk3288-veyron-tiger.dts | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/boot/dts/rk3288-veyron-jaq.dts b/arch/arm/boot/dts/rk3288-veyron-jaq.dts
> index af77ab20586d..4a148cf1defc 100644
> --- a/arch/arm/boot/dts/rk3288-veyron-jaq.dts
> +++ b/arch/arm/boot/dts/rk3288-veyron-jaq.dts
> @@ -20,7 +20,7 @@ / {
>
> &backlight {
> /* Jaq panel PWM must be >= 3%, so start non-zero brightness at 8 */
> - brightness-levels = <0 8 255>;
> + brightness-levels = <8 255>;
> num-interpolated-steps = <247>;
> };
>
> diff --git a/arch/arm/boot/dts/rk3288-veyron-minnie.dts b/arch/arm/boot/dts/rk3288-veyron-minnie.dts
> index f8b69e0a16a0..82fc6fba9999 100644
> --- a/arch/arm/boot/dts/rk3288-veyron-minnie.dts
> +++ b/arch/arm/boot/dts/rk3288-veyron-minnie.dts
> @@ -39,7 +39,7 @@ volum_up {
>
> &backlight {
> /* Minnie panel PWM must be >= 1%, so start non-zero brightness at 3 */
> - brightness-levels = <0 3 255>;
> + brightness-levels = <3 255>;
> num-interpolated-steps = <252>;
> };
>
> diff --git a/arch/arm/boot/dts/rk3288-veyron-tiger.dts b/arch/arm/boot/dts/rk3288-veyron-tiger.dts
> index 069f0c2c1fdf..52a84cbe7a90 100644
> --- a/arch/arm/boot/dts/rk3288-veyron-tiger.dts
> +++ b/arch/arm/boot/dts/rk3288-veyron-tiger.dts
> @@ -23,7 +23,7 @@ / {
>
> &backlight {
> /* Tiger panel PWM must be >= 1%, so start non-zero brightness at 3 */
> - brightness-levels = <0 3 255>;
> + brightness-levels = <3 255>;
> num-interpolated-steps = <252>;
> };
>
> --
> 2.28.0
>
