Skip to content

Fall back to the kernel backlight for an all-in-one's DP panel #14647

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We鈥檒l occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
omarchybot wants to merge 1 commit into
base: quattro
Choose a base branch
from
Open

Fall back to the kernel backlight for an all-in-one's DP panel #14647

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 10 additions & 1 deletion bin/omarchy-brightness-display
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,17 @@ use_apple_display() {
omarchy-hyprland-monitor-focused-apple "$monitor"
}

# An all-in-one wires its built-in panel to a DP connector, which DDC/CI does not answer.
# When that is the only display and the kernel has a backlight, take the backlight to be its own.
monitor_is_panel_without_ddc() {
[[ $monitor == DP-* ]] &&
hyprctl monitors all -j 2>/dev/null | jq -e --arg monitor "$monitor" 'length == 1 and .[0].name == $monitor' >/dev/null 2>&1 &&
omarchy-hw-display >/dev/null 2>&1 &&
! omarchy-brightness-display-ddc "$monitor" >/dev/null 2>&1

@greptile-apps greptile-apps Bot Oct 9, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

P2 DDC reads run twice

For a lone DP-* display with a kernel backlight and working DDC, this probe discards a successful brightness read before the requested operation runs. Queries and relative changes then issue a second getvcp. Absolute changes also gain an unnecessary read even when the range is already cached.

These extra hardware reads slow brightness adjustments. Reuse the successful probe for the requested operation, and add a read-count check to the lone-DP test.

}

use_ddc_display() {
[[ -n $monitor ]] && ! monitor_is_internal
[[ -n $monitor ]] && ! monitor_is_internal && ! monitor_is_panel_without_ddc
}

if (( $# == 0 )); then
Expand Down
75 changes: 75 additions & 0 deletions test/shell.d/brightness-display-test.sh
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,9 +24,16 @@ SH

cat >"$mock_bin/omarchy-hw-display" <<'SH'
#!/bin/bash
[[ ${NO_BACKLIGHT:-0} == "1" ]] && exit 1
printf 'mock_backlight\n'
SH

cat >"$mock_bin/hyprctl" <<'SH'
#!/bin/bash
default='[{"name":"eDP-1"},{"name":"DP-1"},{"name":"DP-2"}]'
printf '%s\n' "${HYPR_MONITORS:-$default}"
SH

cat >"$mock_bin/brightnessctl" <<'SH'
#!/bin/bash
printf 'brightnessctl %s\n' "$*" >>"$CALL_LOG"
Expand All @@ -45,6 +52,8 @@ Display 1
I2C bus: /dev/i2c-${DDC_BUS:-7}
DRM connector: card1-${DDC_CONNECTOR:-DP-1}
EOF
elif [[ $* == *" setvcp 10 "* ]]; then
[[ ${DDC_WRITE_FAIL:-0} != "1" ]]
elif [[ $* == *" getvcp 10 "* ]]; then
[[ ${DDC_READ_FAIL:-0} == "1" ]] && exit 1
printf 'VCP 10 C %s %s\n' "${DDC_CURRENT:-40}" "${DDC_MAXIMUM:-80}"
Expand Down Expand Up @@ -129,6 +138,72 @@ grep -F 'ddcutil --bus 7 --skip-ddc-checks --noverify setvcp 10 5' "$call_log" >
fail "external low brightness writes the one-percent target"
pass "external low brightness uses a one-percent step"

# An all-in-one's built-in panel on DP-1 is listed by ddcutil but does not answer it.
aio_panel() {
rm -f "$runtime_dir/omarchy-brightness-display-ddc/DP-1.bus"
HYPR_MONITORS='[{"name":"DP-1"}]' DDC_READ_FAIL=1 run_brightness "$@"
}

: >"$call_log"
brightness=$(aio_panel --monitor DP-1) || true
[[ $brightness == "40" ]] || fail "all-in-one panel on a DP connector reads the kernel backlight" "actual: $brightness"
aio_panel --no-osd --monitor DP-1 60%
grep -Fx 'brightnessctl -d mock_backlight set 60%' "$call_log" >/dev/null || \
fail "all-in-one panel on a DP connector sets the kernel backlight" "$(cat "$call_log")"
if grep -F 'setvcp' "$call_log"; then
fail "all-in-one panel on a DP connector writes nothing over DDC"
fi
pass "all-in-one panel on a DP connector falls back to the kernel backlight"

: >"$call_log"
rm -f "$runtime_dir/omarchy-brightness-display-ddc/DP-1.bus"
brightness=$(HYPR_MONITORS='[{"name":"DP-1"}]' run_brightness --monitor DP-1)
[[ $brightness == "50" ]] || fail "a lone DP display that answers DDC keeps DDC" "actual: $brightness"
HYPR_MONITORS='[{"name":"DP-1"}]' run_brightness --no-osd --monitor DP-1 25%
grep -F 'ddcutil --bus 7 --skip-ddc-checks --noverify setvcp 10 20' "$call_log" >/dev/null || \
fail "a lone DP display that answers DDC is set over DDC" "$(cat "$call_log")"
if grep -F 'brightnessctl' "$call_log"; then
fail "a lone DP display that answers DDC leaves the kernel backlight alone"
fi
pass "a lone DP display that answers DDC keeps DDC"

: >"$call_log"
if HYPR_MONITORS='[{"name":"DP-1"}]' DDC_WRITE_FAIL=1 run_brightness --no-osd --monitor DP-1 +5%; then
fail "a failed DDC write is reported"
fi
grep -F 'ddcutil --bus 7 --skip-ddc-checks --noverify setvcp 10 44' "$call_log" >/dev/null || \
fail "a failed DDC write was attempted over DDC" "$(cat "$call_log")"
if grep -F 'brightnessctl' "$call_log"; then
fail "a failed DDC write on a readable display leaves the kernel backlight alone"
fi
pass "a failed DDC write on a readable display leaves the kernel backlight alone"

: >"$call_log"
rm -f "$runtime_dir/omarchy-brightness-display-ddc/DP-1.bus"
if HYPR_MONITORS='[{"name":"DP-1"},{"name":"HDMI-A-1"}]' DDC_READ_FAIL=1 run_brightness --no-osd --monitor DP-1 +5%; then
fail "a DP display without DDC beside another display has no brightness backend"
fi
if grep -F 'brightnessctl' "$call_log"; then
fail "a DP display without DDC beside another display leaves the kernel backlight alone"
fi
pass "a DP display without DDC beside another display leaves the kernel backlight alone"

: >"$call_log"
rm -f "$runtime_dir/omarchy-brightness-display-ddc/DP-1.bus"
if HYPR_MONITORS='[{"name":"DP-1"}]' NO_BACKLIGHT=1 DDC_READ_FAIL=1 run_brightness --no-osd --monitor DP-1 +5%; then
fail "a lone DP display without DDC or a backlight has no brightness backend"
fi
pass "a lone DP display without DDC or a backlight has no brightness backend"

: >"$call_log"
if HYPR_MONITORS='[{"name":"HEADLESS-1"}]' run_brightness --no-osd --monitor HEADLESS-1 +5%; then
fail "a lone virtual output has no brightness backend"
fi
if grep -F 'brightnessctl' "$call_log"; then
fail "a lone virtual output leaves the kernel backlight alone"
fi
pass "a lone virtual output leaves the kernel backlight alone"

cat >"$mock_bin/hyprctl" <<'SH'
#!/bin/bash
printf '%s\n' '[
Expand Down