On Mon, 22 Jul 2019, Matthias Kaehlcke wrote: > On Tue, Jul 09, 2019 at 12:00:03PM -0700, Matthias Kaehlcke wrote: > > Backlight brightness curves can have different shapes. The two main > > types are linear and non-linear curves. The human eye doesn't > > perceive linearly increasing/decreasing brightness as linear (see > > also 88ba95bedb79 "backlight: pwm_bl: Compute brightness of LED > > linearly to human eye"), hence many backlights use non-linear (often > > logarithmic) brightness curves. The type of curve is currently opaque > > to userspace, so userspace often relies on more or less reliable > > heuristics (like the number of brightness levels) to decide whether > > to treat a backlight device as linear or non-linear. > > > > Export the type of the brightness curve via a new sysfs attribute. > > > > Matthias Kaehlcke (4): > > MAINTAINERS: Add entry for stable backlight sysfs ABI documentation > > backlight: Expose brightness curve type through sysfs > > backlight: pwm_bl: Set scale type for CIE 1931 curves > > backlight: pwm_bl: Set scale type for brightness curves specified in > > the DT > > > > .../ABI/testing/sysfs-class-backlight | 26 ++++++++++++++ > > MAINTAINERS | 2 ++ > > drivers/video/backlight/backlight.c | 19 ++++++++++ > > drivers/video/backlight/pwm_bl.c | 35 ++++++++++++++++++- > > include/linux/backlight.h | 8 +++++ > > 5 files changed, 89 insertions(+), 1 deletion(-) > > create mode 100644 Documentation/ABI/testing/sysfs-class-backlight > > ping, any comments on v3? Looks like PATCH 2/4 still needs seeing to. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
