USB4 Wake-On-Connect / Wake-On-Disconnect Ready For Linux 6.2
Since that prior Phoronix article, the wake-on-connect/disconnect handling for USB4 ports support has worked its way from the Thunderbolt development tree and now picked up by Greg Kroah-Hartman as part of the USB subsystem updates.
The Thunderbolt updates for Linux 6.2 have been merged into USB-next ahead of the Linux 6.2 merge window opening next week.
For Linux systems run-time suspended, this allows optionally waking the system upon USB4 connect or disconnect events. The functionality is disabled by default but can be toggled via the new "wakeup" attribute under each USB4 port with sysfs. The patch by Intel engineer Rajat Khandelwal explains, "This patch adds 'wakeup' attribute under 'usb4_portX/power' sysfs attribute and only enables wakes on connect/disconnect to the respective port when 'wakeup' is set to 'enabled'. The attribute is set to 'disabled' by default." A small but nice feature for some use-cases with Linux 6.2.
This patch along with many other changes are queuing in usb-next.