I recently installed Freebsd 13.1 on a GPD MicroPC. All worked well except that many APCI notifications did not happen, leading to problems with the power button, lid switch, and other assorted things.
It turned out the problem is that the EC does not work properly on this hardware unless burst mode is on, e.g. sysctl debug.acpi.ec.burst=1 There's nothing particularly unusual about the hardware on this device, so it's likely that the problem exists on other devices. It's not at all hard to fix if one knows what the problem is, but as ACPI is a large and complex system, this is not something the average user is likely to find. It looks like in 2007 a decision was made to have burst mode off by default because it caused "the EC not to respond for some Acer and Compaq/HP laptops" (commit 675e5627d0bf8236d753e4b4e84c6193841b68ce). Perhaps it's time to turn burst mode on by default or otherwise find a way to automate a functional setting of this mode? Cyrus Rahman
