Matthias Kaehlcke 5105593b6e backlight: pwm_bl: Fix heuristic to determine number of brightness levels ... [ Upstream commit 73fbfc4994 ] With commit 88ba95bedb ("backlight: pwm_bl: Compute brightness of LED linearly to human eye") the number of set bits (aka hweight()) in the PWM period is used in the heuristic to determine the number of brightness levels, when the brightness table isn't specified in the DT. The number of set bits doesn't provide a reliable clue about the length of the period, instead change the heuristic to: nlevels = period / fls(period) Also limit the maximum number of brightness levels to 4096 to avoid excessively large tables. With this the number of levels increases monotonically with the PWM period, until the maximum of 4096 levels is reached: period (ns) # levels 100 16 500 62 1000 111 5000 416 10000 769 50000 3333 100000 4096 Fixes: 88ba95bedb ("backlight: pwm_bl: Compute brightness of LED linearly to human eye") Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2020-01-27 14:50:58 +01:00
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backlight	backlight: pwm_bl: Fix heuristic to determine number of brightness levels	2020-01-27 14:50:58 +01:00
console	vgacon: unconfuse vc_origin when using soft scrollback	2019-01-31 08:14:36 +01:00
fbdev	fbdev: chipsfb: remove set but not used variable 'size'	2020-01-27 14:50:21 +01:00
logo
display_timing.c
hdmi.c	video/hdmi: Fix AVI bar unpack	2019-12-17 20:35:17 +01:00
Kconfig
Makefile
of_display_timing.c
of_videomode.c
vgastate.c
videomode.c