I recently tried running powertop on my Linux desktop. It tells you who is waking up your CPU most often. Regularly waking up your CPU prevents it from sleeping peacefully in power-saving mode. Powertop revealed that activity around a “USB TEAC” device was consistently one of my top “waker-uppers”. Googling USB TEAC revealed it to be a memory card reader. Now up to that point I was unaware my desktop had a memory card reader but after some nosing around I discovered a button I hadn’t noticed before. With mounting excitement I pressed the button...a door opened (with a click) and guess what I found inside? Correct. An unused but oft-probed memory card reader.