> -------- > Emmanuel Vadot writes: > > On Thu, 02 Feb 2023 20:58:58 +0000 > > "Poul-Henning Kamp" <p...@phk.freebsd.dk> wrote: > > > > > -------- > > > parv/FreeBSD writes: > > > > > > > > Does backlight(8) works for you? > > > > > > > > Thanks for the clue. It does! It does ... > > > > > > > > - I get the same number back via "backlight" without any arguments as > > > > what I gave it earlier. There was no reporting of value being > > > > subtracted by one; > > > > > > Sorry for the delay in reporting back. > > > > > > I consistently read one less back, except for 0 and 100. > > > > Even 50 ? > > # backlight > brightness: 0 > # backlight 50 > # backlight > brightness: 49 > # backlight 25 > # backlight > brightness: 24 > # backlight 75 > # backlight > brightness: 74 > > yes
This smells like a zero-bias byte rounding issue... Ie, if the backlight intensity register is 8 bit, having values 0 to 255, and we scale 50% to 256 * 50% == 128 or do we scale to 255 * 50% == 127, and then reverse it as 127/255 == 49. > > > So if you have, let's say brightness at 50%, and you plug an external > > monitor, brightness goes up to 100% ? > > No, plugging and unplugging does not change the backlight. > > But when the screen saver has kicked in, and I wake it up again, it comes > back at 100, (and reads back as 100) > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > > -- Rod Grimes rgri...@freebsd.org
