Re: ACPI exception with 2.6.29-rc6

From: Robert Hancock
Date: Tue Feb 24 2009 - 19:15:18 EST


Heinz Diehl wrote:
Hi,

booting 2.6.29-rc6 shows the following in boot.log:

[....]
<7>bus: 00 index 4 mmio: [230000000, fcffffffff]
<6>ACPI: bus type pci registered
<5>PCI: MCFG configuration 0: base f0000000 segment 0 buses 0 - 127
<5>PCI: MCFG area at f0000000 reserved in E820
<6>PCI: Using MMCONFIG at f0000000 - f7ffffff
<6>PCI: Using configuration type 1 for base access
<4>bio: create slab <bio-0> at 0
<7>ACPI: EC: Look up EC in DSDT
--> <3>ACPI: Denied BIOS AML access to invalid port 0x4d0+0x2 (ELCR)
--> <4>ACPI Exception (dsopcode-0419): AE_AML_ILLEGAL_ADDRESS, During address validation of OpRegion [ELCR] [20081204]

Your BIOS defines an operation region on some IO addresses that the kernel will not allow it to access since they are things that BIOS AML code is not supposed to be poking with. This check was recently added. Windows XP and later also disallow AML access to these registers.

Note that this doesn't necessarily mean that the BIOS is actually trying to access those registers. On my A8N-SLI Deluxe machine, the ACPI AML defines an operation region for the ELCR register, but it doesn't seem like it is ever used.

In any case.. nothing to really worry about.

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