USB: core: Add wireless_status sysfs attribute
Add a wireless_status sysfs attribute to USB devices to keep track of whether a USB device that's comprised of a receiver dongle and an emitter device over a, most of the time proprietary, wireless link has its emitter connected or disconnected. This will be used by user-space OS components to determine whether the battery-powered part of the device is wirelessly connected or not, allowing, for example: - upower to hide the battery for devices where the device is turned off but the receiver plugged in, rather than showing 0%, or other values that could be confusing to users - Pipewire to hide a headset from the list of possible inputs or outputs or route audio appropriately if the headset is suddenly turned off, or turned on - libinput to determine whether a keyboard or mouse is present when its receiver is plugged in. This is done at the USB interface level as: - the interface on which the wireless status is detected is sometimes not the same as where it could be consumed (eg. the audio interface on a headset dongle will still appear even if the headset is turned off), and we cannot have synchronisation of status across subsystems. - this behaviour is not specific to HID devices, even if the protocols used to determine whether or not the remote device is connected can be HID. This is not an attribute that is meant to replace protocol specific APIs, such as the ones available for WWAN, WLAN/Wi-Fi, or Bluetooth or any other sort of networking, but solely for wireless devices with an ad-hoc “lose it and your device is e-waste” receiver dongle. The USB interface will only be exporting the wireless_status sysfs attribute if it gets set through the API exported in the next commit. Signed-off-by:Bastien Nocera <hadess@hadess.net> Acked-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by:
Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/20230302105555.51417-4-hadess@hadess.netSigned-off-by:
Benjamin Tissoires <benjamin.tissoires@redhat.com>
Showing
Please register or sign in to comment