Could not change brightness anymore with i915kms & acpi_video modules c 202211

Hi there,

Since around 2022-11, I am unable to change display brightness
of the display of a Framework laptop (Intel i5-1135G7, Iris
Xe iGPU) with "i915kms" module (from "drm-510-kmod" package/port)
& "acpi_video" (FreeBSD) kernel module.

Earlier I was able to change brightness via "hw.acpi.video" MIB ...

# - Need to have both "i915kms" & "acpi_video" modules already loaded.
#
# 20221120 - These MIBs do not work anymore as they are missing.
hw.acpi.video.lcd0.economy=10
hw.acpi.video.lcd0.fullpower=40
hw.acpi.video.lcd0.brightness=15


... now the whole of "hw.acpi.video" stub is missing. Nothing has
changed in terms of how/when "i915kms" & "acpi_video" are loaded (via
"kld_list" variable via "/etc/rc.conf" in that order).

What am I missing?


- parv


## /etc/rc.conf :
clear_tmp_enable="YES"
sendmail_enable="NONE"
sshd_enable="YES"
zfs_enable="YES"
dumpdev="AUTO"

hostname="luna"

devmatch_blacklist="ng_ubt"
devmatch_blacklist="$devmatch_blacklist if_iwlwifi"

moused_enable="YES"

kld_list="filemon"

# As of 20220316 on 14-CURRENT order of values assigned to a variable
matters
# enough that assigning "acpi_video" after "i915kms" is sufficient.
#
# WARNING - After loading 'acpi_video' module, brightness suddenly increases
# blindingly.
#
# XXX: If i915kms does not load properly on boot, say after world install,
will
#      see a blank screen & Ctrl-Alt-{Delete,Backspace,Escape} do not seem
to
#      work; need a hard reboot.
#
# 20230120 - Since around 2022-11 or 2022-12, order has no effect on
brightness.
kld_list="$kld_list i915kms"
kld_list="$kld_list acpi_video"

# Attemp to maximize battery life.
power_profile='economy'
economy_cx_lowest='Cmax'
performance_cx_lowest='C2'

wifibox_enable="YES"
defaultrouter="10.0.0.1"
defaultroot_delay="10"
ifconfig_wifibox0="SYNCDHCP"
background_dhclient_wifibox0="YES"

ntpd_enable="YES"
ntpd_flags="-G"
dbus_enable="YES"
smartd_enable="YES"

## /etc/sysctl.conf :
kern.randompid=1
vfs.usermount=1

kern.vt.kbd_halt=1
kern.vt.kbd_poweroff=1
kern.vt.kbd_reboot=1
kern.vt.kbd_debug=1
kern.vt.kbd_panic=1

vfs.zfs.arc.max=30064771072

dev.hwpstate_intel.0.epp=70
dev.hwpstate_intel.1.epp=70
dev.hwpstate_intel.2.epp=100
dev.hwpstate_intel.3.epp=100
dev.hwpstate_intel.4.epp=100
dev.hwpstate_intel.5.epp=100
dev.hwpstate_intel.6.epp=100
dev.hwpstate_intel.7.epp=100

kern.timecounter.hardware='HPET'

hw.acpi.lid_switch_state='S5'
hw.acpi.sleep_button_state='S5'

# 'acpi_video' module needs to be loaded after 'i915kms' module to have LCD
# brightness related MIBs -- hw.acpi.lcd0.* -- to have any effect. This has
# been an issue since 2014, see PR 195116,
# <https://bugs.freebsd.org/bugzilla/show_bug_cgi?id=195116>.
#
# As of 20220316 on 14-CURRENT order of values assigned to a variable
matters
# enough that assigning "acpi_video" after "i915kms" to "$kld_list" in
# "/etc/rc.conf" is sufficient.
#
# WARNING - After loading 'acpi_video' module, brightness suddenly increases
# blindinly.
#
# Default of 50 for 'hw.acpi.video.lcd0.brightness' rather too bright; 100
is
# blinding.
# - Need to have both "i915kms" & "acpi_video" modules already loaded.
#
# 20221120 - These MIBs do not work anymore as they are missing.
#hw.acpi.video.lcd0.economy=10
#hw.acpi.video.lcd0.fullpower=40
#hw.acpi.video.lcd0.brightness=15

# Power management with "i915kms" module from "drm-devel-kmod" (14-CURRENT)
# package.
# - only in "/boot/loader.conf" ...
#
#     compat.linuxkpi.i915_enable_dc=2
#     compat.linuxkpi.i915_disable_power_well=<-1|0|1>
#
#  ... that means need to load i915kms in "/boot/loader.conf" too.?
#
compat.linuxkpi.i915_fastboot=1
compat.linuxkpi.i915_enable_fbc=1

## /boot/loader.conf :
cryptodev_load="YES"
zfs_load="YES"

kern.msgbufsize=1146880

ums_load="YES"
hms_load="YES"

hw.vga.textmode=0
kern.vty=vt

# Need to load after i915kms module to have effect; so is loaded via
# /etc/rc.conf instead by adding it to $kld_list after "i915kms" as in
# 'kld_list="i915kms acpi_video"'.
#acpi_video_load="YES"

machdep.hwpstate_pkg_ctrl=0
coretemp_load="YES"

## From "/etc/rc.conf" ...
# Power management with "i915kms" module from "drm-devel-kmod" (14-CURRENT)
# package.
# - only in "/boot/loader.conf" ...
#
#     compat.linuxkpi.i915_enable_dc=2
#     compat.linuxkpi.i915_disable_power_well=<-1|0|1>
#
#  ... that means need to load i915kms in "/boot/loader.conf" too.?
#
#compat.linuxkpi.i915_fastboot=1
#compat.linuxkpi.i915_enable_fbc=1

hw.pci.do_power_nodriver=2