The server provides 64 Kbytes of I/O address space. With the increasing number of PCIe devices supported on the server, there is a possibility that there is not enough I/O resources for all the devices.
It is safe, but not typically required, for you to disable I/O resource allocation for any cards that are not intended to be used as bootable devices.
Through the BIOS Setup utility, you can enable or disable the I/O resource allocation for each PCIe slot. The default for this option is enabled. When enabled, I/O resources are allocated to the device as normal. When disabled, I/O resources are not allocated to the device.
If there are one or more Sun Quad Port GigabitEthernet PCIe Low Profile Adapter Cards installed in the server, the BIOS might detect a condition where legacy I/O address space resources are exhausted. The following is a common form of error that might be logged:
6491 Tue Dec 7 14:19:57 2010 IPMI Log minor ID = a5a9 : 12/07/2010 : 14:19:57 : System Firmware Error : sensor number = 0x00 : PCI resource exhaustion : Bus 147 Device 0 Func 0 6490 Tue Dec 7 14:19:57 2010 IPMI Log minor ID = a5a8 : 12/07/2010 : 14:19:57 : System Firmware Error : sensor number = 0x00 : PCI resource exhaustion : Bus 147 Device 0 Func 1
To eliminate the PCI resource exhaustion condition, disable I/O resource allocation for any slot in which the Quad GigabitEthernet card is installed unless you intend to use that card as a bootable device.
If you intend to use that card as a bootable device and you are encountering a PCI resource exhaustion event for that specific device, then you must disable I/O allocation for some of the other cards in the server.