Upon further investigation, it would appear that the kernel is not producing uevents for the AC power device, though the kernel is producing events for the battery. This is a kernel bug, it would appear.
However, I wonder if it would be possible to have upowerd explicitly check the line_power devices when a battery state change occurs, since the sysfs interface does correctly report the connected status of the AC adapter.
Upon further investigation, it would appear that the kernel is not producing uevents for the AC power device, though the kernel is producing events for the battery. This is a kernel bug, it would appear.
However, I wonder if it would be possible to have upowerd explicitly check the line_power devices when a battery state change occurs, since the sysfs interface does correctly report the connected status of the AC adapter.