CVS commit: src/sys/dev/acpi

[Jukka Ruohonen <jruoho%netbsd.org@localhost>]

Module Name:    src
Committed By:   jruoho
Date:           Sun Jun  6 18:56:10 UTC 2010

Modified Files:
        src/sys/dev/acpi: acpi_ec.c

Log Message:
We can no longer explicitly clear a GPE by calling AcpiClearGpe() in the
interrupt handler. However, all edge-triggered GPEs should already be
cleared before our GPE handler has a chance to run.

The reason can be found from the changes in the locking primitives of
ACPICA. All GPE operations now use a spin mutex on AcpiGbl_GpeLock, acquired
via AcpiOsAcquireLock(). This same lock is now acquired unconditionally in
the AcpiClearGpe() function. This causes a deadlock of the following form:

  ...

  AcpiEvGpeDetect() : acquire AcpiGbl_GpeLock;

          -> AcpiEvGpeDispatch();

                  -> acpiec_gpe_handler();

                          -> AcpiClearGpe() : acquire AcpiGbl_GpeLock;

                                  -> panic.


To generate a diff of this commit:
cvs rdiff -u -r1.66 -r1.67 src/sys/dev/acpi/acpi_ec.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.