Hello, I have tested this on my Pinebook Pro and I can confirm that everything seems to work alright. Tested-by: Nikola Radojević <nikola@xxxxxxxxxxxx> On 24/08/04 11:10PM, Dragan Simic wrote: > Increase the frequency of the PWM signal that drives the LED backlight of > the Pinebook Pro's panel, from about 1.35 KHz (which equals to the PWM > period of 740,740 ns), to exactly 8 kHz (which equals to the PWM period of > 125,000 ns). Using a higher PWM frequency for the panel backlight, which > reduces the flicker, can only be beneficial to the end users' eyes. > > On top of that, increasing the backlight PWM signal frequency reportedly > eliminates the buzzing emitted from the Pinebook Pro's built-in speakers > when certain backlight levels are set, which cause some weird interference > with some of the components of the Pinebook Pro's audio chain. > > The old value for the backlight PWM period, i.e. 740,740 ns, is pretty much > an arbitrary value that was selected during the very early bring-up of the > Pinebook Pro, only because that value seemed to minimize horizontal line > distortion on the display, which resulted from the old X.org drivers causing > screen tearing when dragging windows around. That's no longer an issue, so > there are no reasons to stick with the old PWM period value. > > The lower and the upper backlight PWM frequency limits for the Pinebook Pro's > panel, according to its datasheet, are 200 Hz and 10 kHz, respectively. [1] > These changes still leave some headroom, which may have some positive effects > on the lifetime expectancy of the panel's backlight LEDs. > > [1] https://files.pine64.org/doc/datasheet/PinebookPro/NV140FHM-N49_Rev.P0_20160804_201710235838.pdf > > Fixes: 5a65505a6988 ("arm64: dts: rockchip: Add initial support for Pinebook Pro") > Cc: stable@xxxxxxxxxxxxxxx > Reported-by: Nikola Radojevic <nikola@xxxxxxxxxxxx> > Signed-off-by: Dragan Simic <dsimic@xxxxxxxxxxx> > --- > arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts b/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts > index 294eb2de263d..b3f76cc2d6e1 100644 > --- a/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts > +++ b/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts > @@ -32,7 +32,7 @@ chosen { > backlight: edp-backlight { > compatible = "pwm-backlight"; > power-supply = <&vcc_12v>; > - pwms = <&pwm0 0 740740 0>; > + pwms = <&pwm0 0 125000 0>; > }; > > bat: battery {
