RE: [ACPI] Method execution failed

[Moore, R. <rob...@in...>]

This is a bug in the ASL/AML for this machine.  Methods that are
declared "NotSerialized" are forbidden from creating objects within the
namespace (or at least forbidden from creating names that will clash).

There is a fix to the ACPI code that detects this problem and changes
"NotSerialized" to "Serialized" on the fly.  There is also a runtime
option to force all control methods to be "Serialized".

Bob


> -----Original Message-----
> From: acp...@li... [mailto:acpi-devel-
> ad...@li...] On Behalf Of Alex Williamson
> Sent: Friday, August 06, 2004 9:48 AM
> To: acpi-devel
> Subject: [ACPI] Method execution failed
>=20
>=20
>    I think there's a locking issue w/ namespace for concurrent calls
to
> acpi_evaluate_object().  FWIW, these concurrent calls are coming in
> through my acpi sysfs patch, so it could be a bug in that code.  If I
> serialize calls into acpi_evaluate_object(), it works fine, but I
don't
> see a global lock for this, so I think the problem is more general.
If
> I make lots of calls to evaluate the same _BBN object, I start seeing
> these:
>=20
> ACPI-0279: *** Error: Looking up [LBAS] in namespace,
AE_ALREADY_EXISTS
> ACPI-1133: *** Error: Method execution failed [\LBA_.BBN_] (Node
> e00000407fd
>=20
> This starts at acpi_ds_load1_begin_op() doing a path lookup,
presumably
> expecting not to find the path with flag ACPI_NS_ERROR_IF_FOUND.  The
> AML for the method is:
>=20
> 0000000: a45c 2e4c 4241 5f42 424e 5f5e 5f55 4944  .\.LBA_BBN_^_UID
>=20
> The first part of the _SB/LBA/BBN_ AML looks like this:
>=20
> 0000000: 084c 4241 5311 030a 408a 4c42 4153 0056  .LBAS...@.LBAS.V
> 0000010: 414c 448a 4c42 4153 0a04 4c46 4c47 8a4c  ALD.LBAS..LFLG.L
> ...
>=20
> The LBA/BBN_ method appears to make an object named LBAS.  When
calling
> this multiple times, each instance wants to not find this object and
> then create it.  However, the namespace lock is given up around method
> execution, so it seems we have some races.  Am I completely mis-
> interpreting the problem, or does this sound plausible?  I don't
really
> know how to read AML, so this is just a guess.  Do we need to be more
> stringent on locking namespace, or is there a bug in the AML I'm
> calling?  Thanks,
>=20
> 	Alex
>=20
> --
> Alex Williamson                             HP Linux & Open Source Lab