Locking out AML code

Hector Martin
2009-07-07T14:08:05Z

I'm writing a driver to access some EC-related functionality on some
Acer laptops. This uses a separate IO port interface and cannot be done
using the standard ec_read / ec_write ACPI functions. The DSDT also
accesses these IO ports for a few things (most notably display
brightness and some WMI methods). Is there a lock I can hold (from
outside the ACPI subsystem) that will lock out AML method execution
while I poke the hardware?

FWIW, the Windows drivers from Acer also access those IO ports directly
(from userspace, no less, with a dumb kernel driver to provide port I/O
to userspace and in the process introduce a huge security hole of
course). There is no way of talking to this hardware via DSDT methods.

--
Hector Martin (hector@marcansoft.com)
Public Key: http://www.marcansoft.com/marcan.asc