--- name: "gmobile.udev" section: "5" platform: "linux" package: "libgmobile" version: "0.7.4-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/gmobile.udev" --- # gmobile.udev(5) Device configuration for gmobile ## Name gmobile.udev - Device configuration for gmobile ## DESCRIPTION **gmobile** allows one to configure certain aspects through udev's hwdb \ The following properties are supported: ## WAKEUP KEYS An input device's wakeup keys specify which keys unblank the screen of an idle device. By default all keys are wakeup keys. The default can be changed on a per keyboard level via ``` GM_WAKEUP_KEY_DEFAULT=0 ``` The behaviour of individual keys can be changed by giving their keycodes e.g. ``` GM_WAKEUP_KEY_=[0|1] ``` The keycode is the linux event code. Note that gmobile merely provides that information. The Wayland compositor is responsible for applying it. For details on how to add these properties to hwdb see below. ## TORCH BRIGHTNESS A LED that is uses as camera flash can also be used as torch. The minimum torch brightness should still be visible to the user to avoid battery drain. This is usually the case at level **1**. The **GM\_TORCH\_MIN\_BRIGHTNESS** allows to override this value. ``` GM_TORCH_MIN_BRIGHTNESS=10 ``` Note that gmobile merely provides that information. The applications using the flash as torch is responsible for applying it. For details on how to add these properties to hwdb see below. ## CONFIGURING HWDB The hwdb contains a set of match rules that assign udev properties that become available when the device is connected. This section only describes the hwdb in relation to gmobile, it is not full documentation on how the hwdb works. For that please see the **[hwdb(7)](/hwdb/7.md)** man page. gmobile's use of the hwdb is limited to properties systemd and custom rules files (where available) provide. ### Querying the hwdb gmobile currently only uses device nodes in the form of **/dev/input/eventX** where X is the number of the specific device. Running **libinput debug-events** lists all devices currently available to libinput and their event node name: ``` $> sudo libinput debug-events -event0 DEVICE_ADDED gpio-keys seat0 default group1 cap:k -event2 DEVICE_ADDED 30370000.snvs:snvs-powerkey seat0 default group2 cap:k -event3 DEVICE_ADDED generic ft5x06 (f0) seat0 default group3 cap:t ntouches 10 calib ... ``` Note the event node name for your device and translate it into a syspath in the form of **/sys/class/input/eventX**. This path can be supplied to **udevadm** **info** ``` $> udevadm info -p /sys/class/input/event0/ P: /devices/platform/gpio-keys/input/input0/event0 M: event0 R: 0 U: input D: c 13:64 N: input/event0 L: 0 S: input/by-path/platform-gpio-keys-event E: DEVPATH=/devices/platform/gpio-keys/input/input0/event0 E: SUBSYSTEM=input E: DEVNAME=/dev/input/event0 E: MAJOR=13 E: MINOR=64 E: USEC_INITIALIZED=5327886 E: ID_INPUT=1 E: ID_INPUT_KEY=1 E: ID_PATH=platform-gpio-keys E: ID_PATH_TAG=platform-gpio-keys E: GM_WAKEUP_KEY_114=0 E: GM_WAKEUP_KEY_115=0 … ``` Lines starting with **E:** are udev properties available to applications. Properties added by gmobile all have a *GM\_* prefix. They are only present if a hwdb entry matches. ### Reloading the hwdb The actual hwdb is stored in a binary file on-disk and must be updated manually whenever a **.hwdb** file changes. This is required both when a user manually edits the **.hwdb** file or when gmobile ships an updated set of entries. To update the binary file on-disk, run: ``` sudo systemd-hwdb update ``` Then, to trigger a reload of all properties on your device, run: ``` sudo udevadm trigger /sys/class/input/eventX ``` Then check with **udevadm info** whether the properties were updated, see *Querying the hwdb*. If a new property does not appear on the device, use **udevadm** **test** to check for error messages by udev and the hwdb (e.g. syntax errors in the udev rules files). ``` sudo udevadm test /sys/class/input/eventX ``` ### Modifying the hwdb This section applies to users that need to add, change, or remove a hwdb entry for their device. Note that **the hwdb is not part of the public API** **and may change at any time**. Once a device has been made to work, the change must be submitted to the gmobile repository \. hwdb entries are only applied if a udev rules calls out to the hwdb with the right match format. gmobile ships with a set of rules to query the hwdb, the different rules are reflected by their prefix. Again, **this is not part** **of the public API**. gmobile's matches are composed of a literal "gmobile", then either the device name (prefixed with *name:*) followed by the machine's first device tree compatible (prefixed with *dt:*) or dmi modalias. For example: ``` gmobile:name:gpio-keys:dt:purism,librem5* ``` The device name is available in the device's */sys/class/input/eventX/device/name* while the device tree compatible is available in */sys/firmware/devicetree/base/compatible*. The hwdb match string is the first portion of the hwdb entry. The second portion is the property to set. Each hwdb entry may match on multiple devices and may apply multiple properties. For example: ``` gmobile:name:gpio-keys:dt:purism,librem5* GM_WAKEUP_KEY_114=0 GM_WAKEUP_KEY_115=0 ``` In the example above the matching gpio-keys device will have both properties applied. The hwdb does not allow removing properties. Where a property must be unset, it should be set to 0. For testing any user-specific hwdb entries should be placed in a file */etc/udev/hwdb.d/99-gmobile.hwdb* but please make sure to submit them upstream as the hwdb format might change without notice. ## See also **[hwdb(7)](/hwdb/7.md)** **[systemd-hwdb(8)](/systemd-hwdb/8.md)** **[phoc(1)](/phoc/1.md)** **[phosh(1)](/phosh/1.md)**