| Message ID | 20201021220404.v3.1.I96b8d872ec51171f19274e43e96cadc092881271@changeid (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | PWM backlight interpolation adjustments | expand |
Hi, On Wed, Oct 21, 2020 at 10:05 PM Alexandru Stan <amstan@chromium.org> wrote: > > The extra 0 only adds one point in the userspace visible range, > so this change is almost a noop with the current driver behavior. > > 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. > > Furthermore after adding "backlight: pwm_bl: Fix interpolation" patch, > the backlight interpolation will work a little differently. So we need > to preemptively remove the 0-3 segment since otherwise we would have a > 252 long interpolation that would slowly go between 0 and 3, looking > really bad in userspace. So it's almost a noop/cleanup now, but it will > be required in the future. > > Signed-off-by: Alexandru Stan <amstan@chromium.org> > --- > > 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(-) Reviewed-by: Douglas Anderson <dianders@chromium.org>
On Wed, Oct 21, 2020 at 10:04:43PM -0700, Alexandru Stan wrote: > The extra 0 only adds one point in the userspace visible range, > so this change is almost a noop with the current driver behavior. > > 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. > > Furthermore after adding "backlight: pwm_bl: Fix interpolation" patch, > the backlight interpolation will work a little differently. So we need > to preemptively remove the 0-3 segment since otherwise we would have a > 252 long interpolation that would slowly go between 0 and 3, looking > really bad in userspace. So it's almost a noop/cleanup now, but it will > be required in the future. > > Signed-off-by: Alexandru Stan <amstan@chromium.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> > --- > > 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
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>; };
The extra 0 only adds one point in the userspace visible range, so this change is almost a noop with the current driver behavior. 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. Furthermore after adding "backlight: pwm_bl: Fix interpolation" patch, the backlight interpolation will work a little differently. So we need to preemptively remove the 0-3 segment since otherwise we would have a 252 long interpolation that would slowly go between 0 and 3, looking really bad in userspace. So it's almost a noop/cleanup now, but it will be required in the future. Signed-off-by: Alexandru Stan <amstan@chromium.org> --- 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(-)