Sun Microsystems Fire X4800, Installation Manual

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I/O Space Allocation
The PC architecture provides a total of 64 Kbytes of I/O space. By default, the BIOS allocates
I/O space as shown in the Default I/O Allocation table.
■
The total available space appears in the Maximum Allocation column.
■
Some of the space is required for onboard devices. The remaining space appears in the Space
Available column.
■
PCIe express modules and fabric expansion modules require either 4 Kbytes or 8 Kbytes,
depending on whether they have a PCIe bridge or not.
TABLE 2
Default I/O Allocation
CPU Module Slot Maxmum Allocation Space Available for EMs and FEMs EM Slots
3 16 k 12k 3.1, 3.0
2 8k 4k 2.1, 2.0
1 16k 12k 1.1, 1.0
0 (master) 24k 8k 0.1, 0.0
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How to Determine Whether You Need to Allocate Option ROM and I/O
Space
If you add a PCIe express module or a fabric expansion module to an eight-socket system (with
CPU modules in all four slots), when the system boots, the BIOS might not be able to allocate
option ROM or I/O space to all the devices that require it.
If this happens, when you boot, POST generates error messages. These identify any devices that
have not had option ROM or I/O space allocated.
Power on the system to start the BIOS.
During POST, look for one or more messages, such as these.
■
For option ROM, the messages look like this:
Warning: Out of option ROM space for device EM0.1 [04:00:01]
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For I/O space, the messages look like this:
Warning: Not enough IO address space allocated for device EM0.0 [0A:00:01]
Warning: Not enough IO address space allocated for device EM0.0 [0A:00:00]
Warning: Not enough IO address space allocated for device EM0.1 [05:00:01]
Warning: Not enough IO address space allocated for device EM0.1 [05:00:00]
Warning: Not enough IO address space allocated for device EM0.1 [04:00:01]
Warning: Not enough IO address space allocated for device EM0.1 [04:00:00]
Each slot can generate several messages. This is normal.
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Option ROM and I/O Space Allocation
Sun Fire X4800 Server Installation Guide • —12, March 2011 126