Benign Messages: NorthBridge GART Aperture Size

Warning Messages: (1) Your BIOS doesn’t leave a aperture memory hole. (2) Please enable the IOMMU option in the BIOS setup. (3) This costs you 64 MB of RAM. All benign.

Problem

The Linux operating system produces a warning message that states the NorthBridge GART aperture size is too small (32 Mbytes).

The size of the GART aperture that the Linux OS finds when the IOMMU subsystem is initialized is 32 Mbytes. However, Linux expects the minimum size of the aperture to be 64 Mbytes. This issue arises because the check that Linux uses to determine validity is not complete, and thus the warning message is premature. Regardless of this message, Linux will allocate 64 Mbytes of aperture space and use that space for DMA and PCI devices.

Impacted OS: RHEL AS 4-U3; RHEL AS 4-U4; SLES9-SP3

Impacted Hardware: All server modules (X8400, X8420, X8440)

Workaround

This is a benign warning message that does not affect system functionality in any way.