The backwards-incompatible changes in libddcutil.so.5 are documented at
https://www.ddcutil.com/c_api_200/ - a quick grep says that the only affected
symbol appearing in E is ddca_set_global_sleep_multiplier (which is already
optional).
This change does not make any of the changes suggested in the "Library
Initialization" section of the above doc.
1. use max valu in the get and store it once a get has been done so it
will get backlight level right on unsuaul monitors that do not use
0->100
2. detect as an error dinfing 2 screesn with the same edid and log it
3. use ddca_enable_sleep_suppression() to try speed up things a bit to
sleep less inside ddcutil
beating on ddc support to make it solid. dealing with some bad screens
that don't respond, a libddcutil that was doing a printf messing up
the message stream from e_system to e .... and more.
so if monitor is buys waking up from dpms, it may not be bothering to
do what we asked... but the sets of the propety say they succeed, so
use the get at the end of a fade in run to see if we get the target
brightness within some delta and it's one of our standard brightnesses
(1.0, normal or dim) and retry a few times until we succeed or give
up. this ensures on wakupe your monitors end up at their target
brightness even with some hiccups as opposed to stay dim. not much we
can do about iffy hardware or libddcutil (not sure which is to blame)
other than do workarounds like this.
also add logging so you can see what is being asked and if it succeeds
or fails according to libddcutil.
just by luck the queue "play catchup" happens to have a classic
scheduling issue. one screen always wins, the other always loses as we
play catch-up in the request queue so one is starved of "scheduling
slots" while the othe rgets them all. this fixes that by moving the
entire request queue into the thread work queue in one go so they all
get an equal chance. now botjh my desktop monitors dim smoothly on
idle like my laptop... smooooooooood
This adds ddc monitor control and glues it into the backlight system.
A result of this is now backlgiht control gadgets work screen by
screen and even on desktop monitors as well as on a laptop panel. If
you now put a backlight gadget on a shelf on each screen... it will
control THAT screen's backlight.
This requires libddcutil to be installed. That will require i2c
modules (i2c-dev specifically). This means that this is likely not
going to do anything useful on bsd's... unless libddcutil happens to
work there by chance.
so install ddcutil/libddcutil. ensure it's in ld.so.conf so setuid
root processes find it (as LD_LIBRARY_PATH won't help) and enjoy your
new funcky per-screen backlight controls... :)
@feature
Ross Vandegrift
Carsten Haitzler