Compaq 108164-003 - ProLiant - 800 Integration Notes page 44

PCI Bus Numbering in a Microsoft Windows NT Environment
Configuration A: Test 1 – Initial Configuration
Even though PCI bus numbers are
assigned during every boot
process, the assignment is exactly
the same as long as the
configuration remains the same.
Bus
Detection
Order/
Controller
Discovery
1st
2nd
3rd
4th
5th
6th
7th
8th
th
9
10th
Reviewing the Test 1 Configuration
In Test 1, the PCI BIOS begins the discovery process by identifying buses on the Primary PCI
Bus. It continues to the Secondary PCI Bus looking for PCI buses and or bridges. As each bus is
detected it is assigned a bus number starting at bus 0, the PCI BIOS then assigns bus numbers to
13UK-1200A-WWEN
This bus number and controller discovery test was performed on a simple
configuration in a dual-peer PCI ProLiant 6500 server (see Table 13). This
configuration is described as simple because it contains only two non-
bridged PCI network controllers.
Table 13. PCI BIOS bus detection in a ProLiant 6500 – before adding a
bridged controller
Slot PCI Bridge/
Number Controller Type
– Test 1
Primary Host to PCI Bus
Bus (0) Bridge
Slot 1 Netelligent
10/100 TX
Slot 2 Empty
Seconda
Host to PCI Bus
ry Bus
Bridge
(1)
Slot 3 Empty
Slot 4 Netelligent
10/100 TX
Slot 5 Empty
Slot 6 Empty
Slot 7 Empty
Slot 8 Empty
Bus Number Description of PCI BIOS Discovery
Assignment Process
Bus 0 The PCI BIOS discovers the Primary
Bus and assigns it bus 0.
PCI BIOS detects a NIC (no PCI
bridge) in slot 1, it is assigned the
Bus 0
same bus number as the PCI Bus
where it resides, and is the first
controller detected by the PCI BIOS.
Discovery process continues to PCI
N/A
slot 2. No PCI controller detected, no
bus number assigned.
Bus 1
The PCI BIOS discovers the
Secondary Bus and increments the
bus number to 1.
Discovery process continues to PCI
N/A
slot 3. No PCI controller detected no
bus number assigned.
PCI BIOS detects a NIC (no PCI
Bus 1
bridge) in slot 4 it is assigned the
same bus number as the PCI Bus
where it resides, bus 1.
N/A
Discovery process continues to PCI
slot 5. No PCI controller detected, no
N/A
bus number assigned.
Discovery process continues to PCI
slot 6. No PCI controller detected, no
N/A
bus number assigned.
Discovery process continues to PCI
N/A slot 7. No PCI controller detected, no
bus number assigned.
Discovery process continues to PCI
slot 8. No PCI controller detected, no
bus number assigned.
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