Add external monitor brightness over DDC/CI
brightnessctl drives the kernel backlight class, which laptop panels have and this desktop does not -- it reports only keyboard and NIC LEDs. So BrightnessControl removed itself and there was no way to dim the screen from Panama at all. DDC/CI is the channel the buttons on a monitor's bezel drive, and it is the only brightness an external display has. Both sources now render a row each, so a machine gets whichever it actually has, or none. Displays are enumerated from sysfs rather than `ddcutil detect`. The kernel publishes the connector-to-bus mapping as /sys/class/drm/<card>-<connector>/ddc along with whether anything is plugged in, which beats parsing detect's undocumented brief output, yields the connector name spelled exactly as Hyprland spells it, and probes only connectors with a monitor attached -- one bus on this machine rather than fourteen, where each empty bus costs a timeout. No model name is read: Hyprland already knows what every output is called, so the UI joins on the connector instead of keeping a second source of truth that could disagree with the Displays page. Writes are debounced, serial, and read back. Serial because DDC/CI has no arbitration and two ddcutil processes on one bus interleave their exchanges and both return garbage. Read back because a write is not a promise: panels clamp to their own range, ignore values while waking from standby, and drop writes that arrive too fast. Without the read the slider would show what Panama asked for rather than what the monitor did, which is the same class of lie as trusting `hyprctl keyword`. Brightness is deliberately not a stored preference. The monitor remembers it and the bezel buttons change it behind Panama's back, so persisting it would mean restoring a value the panel had moved past. The contract runs against fixtures with ddcutil stubbed and both sysfs roots redirected, so it never touches a real monitor. Its fixture reports a maximum of 200 rather than 100 on purpose -- at 100 the scaling arithmetic is the identity and a helper that ignored the reported maximum would pass everything. Verified it catches that, plus a dropped connection-status filter and an unstripped connector prefix. Not yet confirmed against hardware: this machine cannot open any I2C bus yet. ddcutil's udev rule grants that through uaccess but only to devices created after it was installed, so it needs one udevadm trigger. The helper detects exactly that case and returns the command as its error rather than reporting "no displays". Claude-Session: https://claude.ai/code/session_01BRvzt4H8XXLPVH5MyYdk9L
This commit is contained in:
Gabriel Brown
@@ -1,24 +1,44 @@
|
||||
// Backlight slider, via brightnessctl.
|
||||
// Brightness, from whichever source this machine actually has.
|
||||
//
|
||||
// This machine drives an external DisplayPort monitor and has no backlight
|
||||
// class device at all (brightnessctl only reports keyboard/NIC LEDs), so the
|
||||
// row removes itself rather than sitting there as a dead control. Probed once
|
||||
// at startup — backlight devices do not appear and disappear.
|
||||
// Two exist and they are not interchangeable:
|
||||
//
|
||||
// The kernel backlight class, driven by brightnessctl. Laptop panels have it;
|
||||
// this desktop does not -- brightnessctl reports only keyboard and NIC LEDs.
|
||||
//
|
||||
// DDC/CI, the channel the buttons on a monitor's bezel drive. That is the
|
||||
// only brightness an external display has, and it is per-monitor.
|
||||
//
|
||||
// A machine may have neither, either, or both, so this renders a row per source
|
||||
// found and removes itself entirely when there are none, rather than sitting
|
||||
// there as a dead control.
|
||||
//
|
||||
// Connector labels appear only when there is more than one row. A single
|
||||
// slider needs no explanation of which screen it dims.
|
||||
|
||||
import QtQuick
|
||||
import Quickshell
|
||||
import Quickshell.Io
|
||||
import qs.widgets
|
||||
import qs.config
|
||||
import qs.services
|
||||
|
||||
Item {
|
||||
id: root
|
||||
|
||||
property bool available: false
|
||||
property real value: 0
|
||||
property bool backlightAvailable: false
|
||||
property real backlightValue: 0
|
||||
|
||||
visible: root.available
|
||||
implicitHeight: root.available ? 32 : 0
|
||||
readonly property int rowCount: (root.backlightAvailable ? 1 : 0) + Brightness.displays.length
|
||||
readonly property bool labelled: root.rowCount > 1
|
||||
|
||||
visible: root.rowCount > 0
|
||||
implicitHeight: rows.implicitHeight
|
||||
|
||||
// Probing I2C takes on the order of a second, so it waits until the panel
|
||||
// is actually on screen rather than running at shell startup. Monitors do
|
||||
// not come and go, so once is enough.
|
||||
onVisibleChanged: if (visible && !Brightness.scanned) Brightness.refresh()
|
||||
Component.onCompleted: if (root.visible && !Brightness.scanned) Brightness.refresh()
|
||||
|
||||
// `-m` is the machine-readable form: name,class,current,percent,max
|
||||
Process {
|
||||
@@ -34,36 +54,105 @@ Item {
|
||||
const fields = line.split(",");
|
||||
if (fields.length < 5 || fields[1] !== "backlight")
|
||||
continue;
|
||||
root.available = true;
|
||||
root.value = parseInt(fields[3]) / 100;
|
||||
root.backlightAvailable = true;
|
||||
root.backlightValue = parseInt(fields[3]) / 100;
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
function apply(v: real): void {
|
||||
root.value = v;
|
||||
function applyBacklight(v: real): void {
|
||||
root.backlightValue = v;
|
||||
// Never go fully dark: a 0% backlight looks like a broken shell.
|
||||
Quickshell.execDetached(["brightnessctl", "-c", "backlight", "-q", "set", Math.max(1, Math.round(v * 100)) + "%"]);
|
||||
}
|
||||
|
||||
// ValueSlider draws its own leading icon, but symbolic icons need
|
||||
// recolouring to be visible — see ThemedIcon.
|
||||
ThemedIcon {
|
||||
id: glyph
|
||||
Column {
|
||||
id: rows
|
||||
anchors.left: parent.left
|
||||
anchors.leftMargin: 6
|
||||
anchors.verticalCenter: parent.verticalCenter
|
||||
size: 17
|
||||
icon: "display-brightness-symbolic"
|
||||
anchors.right: parent.right
|
||||
spacing: 4
|
||||
|
||||
BrightnessRow {
|
||||
width: rows.width
|
||||
visible: root.backlightAvailable
|
||||
label: "Built-in"
|
||||
value: root.backlightValue
|
||||
onMoved: v => root.applyBacklight(v)
|
||||
}
|
||||
|
||||
Repeater {
|
||||
model: Brightness.displays
|
||||
|
||||
BrightnessRow {
|
||||
required property var modelData
|
||||
width: rows.width
|
||||
// Hyprland already knows what each output is called, so the
|
||||
// name comes from there rather than from a second source that
|
||||
// could disagree with the Displays page. The connector is the
|
||||
// fallback, so a display is never an unlabelled slider.
|
||||
label: Displays.monitorNamed(modelData.connector)?.description || modelData.connector
|
||||
value: modelData.value / 100
|
||||
onMoved: v => Brightness.set(modelData.bus, Math.round(v * 100))
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
ValueSlider {
|
||||
anchors.left: glyph.right
|
||||
anchors.leftMargin: 12
|
||||
anchors.right: parent.right
|
||||
anchors.rightMargin: 32
|
||||
anchors.verticalCenter: parent.verticalCenter
|
||||
value: root.value
|
||||
onMoved: v => root.apply(v)
|
||||
component BrightnessRow: Item {
|
||||
id: row
|
||||
|
||||
property string label: ""
|
||||
property real value: 0
|
||||
signal moved(real value)
|
||||
|
||||
implicitHeight: caption.height + control.height
|
||||
|
||||
Text {
|
||||
id: caption
|
||||
anchors.left: parent.left
|
||||
anchors.right: parent.right
|
||||
anchors.leftMargin: 6
|
||||
anchors.rightMargin: 6
|
||||
anchors.top: parent.top
|
||||
visible: root.labelled
|
||||
height: visible ? implicitHeight + 2 : 0
|
||||
text: row.label
|
||||
color: Theme.fgDim
|
||||
font.family: Theme.fontFamily
|
||||
font.pixelSize: Theme.fontSizeSmall
|
||||
elide: Text.ElideRight
|
||||
}
|
||||
|
||||
// The slider and its glyph share one strip so the two stay aligned
|
||||
// whether or not a caption sits above them. Anchoring the glyph to
|
||||
// both a caption and a centre line instead would conflict, and an
|
||||
// anchor set to undefined is not released.
|
||||
Item {
|
||||
id: control
|
||||
anchors.left: parent.left
|
||||
anchors.right: parent.right
|
||||
anchors.top: caption.bottom
|
||||
height: 32
|
||||
|
||||
// ValueSlider draws its own leading icon, but symbolic icons need
|
||||
// recolouring to be visible — see ThemedIcon.
|
||||
ThemedIcon {
|
||||
id: glyph
|
||||
anchors.left: parent.left
|
||||
anchors.leftMargin: 6
|
||||
anchors.verticalCenter: parent.verticalCenter
|
||||
size: 17
|
||||
icon: "display-brightness-symbolic"
|
||||
}
|
||||
|
||||
ValueSlider {
|
||||
anchors.left: glyph.right
|
||||
anchors.leftMargin: 12
|
||||
anchors.right: parent.right
|
||||
anchors.rightMargin: 32
|
||||
anchors.verticalCenter: parent.verticalCenter
|
||||
value: row.value
|
||||
onMoved: v => row.moved(v)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user