The system provides 64 Kbytes of I/O address space. With the increasing number of PCIe devices supported on the system, there is a possibility that there is not enough I/O resources for all the devices. Setup options are available to 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 Gigabit Ethernet PCIe Low Profile Adapter Cards installed in the server, then 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 2012 IPMI Log minor
ID = a5a9 : 12/07/2012 : 14:19:57 : System Firmware Error :
= 0x00 : PCI resource exhaustion : Bus 147 Device 0 Func 0
6490 Tue Dec 7 14:19:57 2012 IPMI Log minor
ID = a5a8 : 12/07/2012 : 14:19:57 : System Firmware Error :
= 0x00 : PCI resource exhaustion : Bus 147 Device 0 Func 1
To eliminate the PCI resource exhaustion condition, you should disable I/O resource allocation for any slot in which the Quad Gigabit Ethernet 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 it is necessary to disable I/O allocation for some of the other card slots in the system. In general, it is safe, but not typically required, to disable I/O resource allocation for any cards not intended to be used as bootable devices, similar to the disabling of Option ROMs.