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? Thanks Matthias _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
