Re: [PATCH v2 4/4] backlight: pwm_bl: Set scale type for brightness curves specified in the DT

From
Pavel Machek <hidden>
Date
2019-06-26 14:56:29
Also in
dri-devel, linux-pwm, lkml
Reply to
Matthias Kaehlcke, 2019-06-24
On Mon 2019-06-24 13:31:13, Matthias Kaehlcke wrote:
Check if a brightness curve specified in the device tree is linear or
not and set the corresponding property accordingly. This makes the
scale type available to userspace via the 'scale' sysfs attribute.

To determine if a curve is linear it is compared to a interpolated linear
curve between min and max brightness. The curve is considered linear if
no value deviates more than +/-5% of ${brightness_range} from their
interpolated value.
I don't think this works. Some hardware does takes brightness in perceptual units,
converting it in the LED controller.

									Pavel
Thread (11 messages) 11 messages, 3 authors, last reply 2019-07-01
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