Unexpected IO-APIC warning.

[Eskil Heyn Olsen <eskil@neoteris.com>]

I'm booting 2.4.18 on a machine with the intel E7500 motherboard and two
Xeon cpus, and I get the

 WARNING: unexpected IO-APIC, please mail
          to linux-smp@vger.kernel.org

Here's the boot messages ;

Linux version 2.4.18 (eskil@sleipnir) (gcc version 2.96 20000731 (Red
Hat Linux 7.2
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009e800 (usable)
 BIOS-e820: 000000000009e800 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 000000003fef0000 (usable)
 BIOS-e820: 000000003fef0000 - 000000003feff000 (ACPI data)
 BIOS-e820: 000000003feff000 - 000000003ff00000 (ACPI NVS)
 BIOS-e820: 000000003ff00000 - 000000003ff80000 (usable)
 BIOS-e820: 000000003ff80000 - 0000000040000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
 BIOS-e820: 00000000ff800000 - 00000000ffc00000 (reserved)
 BIOS-e820: 00000000fff00000 - 0000000100000000 (reserved)
127MB HIGHMEM available.
found SMP MP-table at 000f66c0
hm, page 000f6000 reserved twice.
hm, page 000f7000 reserved twice.
hm, page 0009e000 reserved twice.
hm, page 0009f000 reserved twice.
On node 0 totalpages: 262016
zone(0): 4096 pages.
zone(1): 225280 pages.
zone(2): 32640 pages.
Intel MultiProcessor Specification v1.4
    Virtual Wire compatibility mode.
OEM ID:   Product ID: SE7500CW2 APIC at: 0xFEE00000
Processor #0 Unknown CPU [15:2] APIC version 20
Processor #6 Unknown CPU [15:2] APIC version 20
I/O APIC #2 Version 32 at 0xFEC00000.
I/O APIC #3 Version 32 at 0xFEC80000.
I/O APIC #4 Version 32 at 0xFEC80400.
Processors: 2
Kernel command line: auto BOOT_IMAGE=factory-reset ro root=305 noconfirm
Initializing CPU#0
Detected 2192.925 MHz processor.
Calibrating delay loop... 4377.80 BogoMIPS
Memory: 1029196k/1048064k available (1138k kernel code, 18412k reserved,
253k data)
Dentry-cache hash table entries: 131072 (order: 8, 1048576 bytes)
Inode-cache hash table entries: 65536 (order: 7, 524288 bytes)
Mount-cache hash table entries: 16384 (order: 5, 131072 bytes)
Buffer-cache hash table entries: 65536 (order: 6, 262144 bytes)
Page-cache hash table entries: 262144 (order: 8, 1048576 bytes)
CPU: L1 I cache: 12K, L1 D cache: 8K
CPU: L2 cache: 512K
CPU: Physical Processor ID: 0
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#0.
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Checking 'hlt' instruction... OK.
POSIX conformance testing by UNIFIX
CPU: L1 I cache: 12K, L1 D cache: 8K
CPU: L2 cache: 512K
CPU: Physical Processor ID: 0
Intel machine check reporting enabled on CPU#0.
CPU0: Intel(R) XEON(TM) CPU 2.20GHz stepping 04
per-CPU timeslice cutoff: 1463.11 usecs.
enabled ExtINT on CPU#0
ESR value before enabling vector: 00000000
ESR value after enabling vector: 00000000
Booting processor 1/6 eip 2000
Initializing CPU#1
masked ExtINT on CPU#1
ESR value before enabling vector: 00000000
ESR value after enabling vector: 00000000
Calibrating delay loop... 4377.80 BogoMIPS
CPU: L1 I cache: 12K, L1 D cache: 8K
CPU: L2 cache: 512K
CPU: Physical Processor ID: 3
Intel machine check reporting enabled on CPU#1.
CPU1: Intel(R) XEON(TM) CPU 2.20GHz stepping 04
Total of 2 processors activated (8755.60 BogoMIPS).
WARNING: No sibling found for CPU 0.
WARNING: No sibling found for CPU 1.
ENABLING IO-APIC IRQs
Setting 2 in the phys_id_present_map
...changing IO-APIC physical APIC ID to 2 ... ok.
Setting 3 in the phys_id_present_map
...changing IO-APIC physical APIC ID to 3 ... ok.
Setting 4 in the phys_id_present_map
...changing IO-APIC physical APIC ID to 4 ... ok.
..TIMER: vector=0x31 pin1=2 pin2=0
testing the IO APIC.......................

 WARNING: unexpected IO-APIC, please mail
          to linux-smp@vger.kernel.org


.................................... done.
Using local APIC timer interrupts.
calibrating APIC timer ...
..... CPU clock speed is 2192.9721 MHz.
..... host bus clock speed is 99.6804 MHz.
cpu: 0, clocks: 996804, slice: 332268
CPU0<T0:996800,T1:664528,D:4,S:332268,C:996804>
cpu: 1, clocks: 996804, slice: 332268
CPU1<T0:996800,T1:332256,D:8,S:332268,C:996804>
checking TSC synchronization across CPUs: passed.
Waiting on wait_init_idle (map = 0x2)
All processors have done init_idle
PCI: PCI BIOS revision 2.10 entry at 0xfd921, last bus=4
PCI: Using configuration type 1
PCI: Probing PCI hardware
Unknown bridge resource 0: assuming transparent
Unknown bridge resource 2: assuming transparent
Unknown bridge resource 0: assuming transparent
Unknown bridge resource 1: assuming transparent
Unknown bridge resource 2: assuming transparent
Unknown bridge resource 0: assuming transparent
Unknown bridge resource 1: assuming transparent
Unknown bridge resource 2: assuming transparent
Unknown bridge resource 2: assuming transparent
PCI: Using IRQ router default [8086/2480] at 00:1f.0
PCI->APIC IRQ transform: (B0,I29,P0) -> 16
PCI->APIC IRQ transform: (B0,I29,P1) -> 19
PCI->APIC IRQ transform: (B0,I31,P0) -> 17
PCI->APIC IRQ transform: (B0,I31,P1) -> 17
PCI->APIC IRQ transform: (B4,I3,P0) -> 21
PCI->APIC IRQ transform: (B4,I4,P0) -> 20
PCI->APIC IRQ transform: (B4,I5,P0) -> 23
PCI->APIC IRQ transform: (B4,I6,P0) -> 22

Let me know if theres anything else you need.

-- 
eskil
---