Specifically, assume that the device is present if evaluation of _STA
method fails.
Before r330957 we ignored any _STA evaluation failure (which was
performed by AcpiGetObjectInfo in ACPICA contrib code) for the purpose
of acpi_DeviceIsPresent and acpi_BatteryIsPresent. ACPICA 20180313
removed evaluation of _STA from AcpiGetObjectInfo. So, we added
evaluation of _STA to acpi_DeviceIsPresent and acpi_BatteryIsPresent.
One important difference is that the new code ignored a failure only if
_STA did not exist (AE_NOT_FOUND). Any other kind of failure was
treated as a fatal failure. Apparently, on some systems we can get
AE_NOT_EXIST when evaluating _STA. And that error is not an evil twin
of AE_NOT_FOUND, despite a very similar name, but a distinct error
related to a missing handler for an ACPI operation region.
It's possible that for some people the problem was already fixed by
changes in ACPICA and/or in acpi_ec driver (or even in BIOS) that fixed
the AE_NOT_EXIST failure related to EC operation region.
This work is based on a great analysis by cem and an earlier patch by
Ali Abdallah <aliovx@gmail.com>.
PR: 227191
Reported by: 0mp
MFC after: 2 weeks
817b71bbb9