Tom> Agree. The question is that how many egde-triggered MSI with Tom> the same vector are generated by e1000 hardware when its Tom> service handler is still running. One piece of information that I just noticed is that all of my tests were done with CONFIG_E1000_NAPI turned on, so I may be hitting some NAPI race condition. Unfortunately I can't try anything on my Dell P4 system (I don't have remote serial access and I'm not in front of the machine, so I can't mess with the network driver). I did do a little more testing on the dual Nocona/Lindenhurst system that I do have remote serial access to (lspci at the end of this email). In my earlier testing I only looked at "ifconfig" and "/proc/interrupts" information -- what I didn't notice was that networking didn't work at all (and tcpdump shows no packets being received). This happens even with NAPI turned off. I added a little more debugging to the driver and it seems that it reads a bogus RX descriptor (status == 0x63, errors == 0x6f). This happens exactly when MSI is turned on, although I have no idea why. Unfortunately I'm afraid that I may be running into some Nocona or Lindenhurst errata on this system. I'll be able to try my P4 system (with 865 chipset) tomorrow. One other thing I don't understand independent of any e1000 issues I'm running into is what could cause this type of message: CPU 0: Machine Check Exception: 0000000000000000 CPU 0: EIP: 00000000 EFLAGS: 00000000 eax: 00000000 ebx: 00000000 ecx: 00000000 edx: 00000000 esi: 00000000 edi: 00000000 ebp: 00000000 esp: 00000000 The "0000000000000000" above is coming from the IA32_MCG_STATUS MSR, and it seems to show a machine check occurring with MCIP ("machine check in progress") == 0 -- any idea how this could happen? Thanks, Roland 0000:00:00.0 Host bridge: Intel Corp. Server Memory Controller Hub (rev 09) 0000:00:00.1 ff00: Intel Corp. Memory Controller Hub Error Reporting Register (rev 09) 0000:00:01.0 System peripheral: Intel Corp. Memory Controller Hub DMA Controller (rev 09) 0000:00:02.0 PCI bridge: Intel Corp. Memory Controller Hub PCI Express Port A0 (rev 09) 0000:00:04.0 PCI bridge: Intel Corp. Memory Controller Hub PCI Express Port B0 (rev 09) 0000:00:05.0 PCI bridge: Intel Corp. Memory Controller Hub PCI Express Port B1 (rev 09) 0000:00:06.0 PCI bridge: Intel Corp. Memory Controller Hub PCI Express Port C0 (rev 09) 0000:00:07.0 PCI bridge: Intel Corp. Memory Controller Hub PCI Express Port C1 (rev 09) 0000:00:08.0 System peripheral: Intel Corp. Memory Controller Hub Extended Configuration Registers (rev 09) 0000:00:1d.0 USB Controller: Intel Corp. 82801EB/ER (ICH5/ICH5R) USB UHCI #1 (rev 02) 0000:00:1d.1 USB Controller: Intel Corp. 82801EB/ER (ICH5/ICH5R) USB UHCI #2 (rev 02) 0000:00:1d.2 USB Controller: Intel Corp. 82801EB/ER (ICH5/ICH5R) USB UHCI #3 (rev 02) 0000:00:1d.7 USB Controller: Intel Corp. 82801EB/ER (ICH5/ICH5R) USB2 EHCI Controller (rev 02) 0000:00:1e.0 PCI bridge: Intel Corp. 82801 PCI Bridge (rev c2) 0000:00:1f.0 ISA bridge: Intel Corp. 82801EB/ER (ICH5/ICH5R) LPC Bridge (rev 02) 0000:00:1f.2 IDE interface: Intel Corp. 82801EB (ICH5) Serial ATA 150 Storage Controller (rev 02) 0000:00:1f.3 SMBus: Intel Corp. 82801EB/ER (ICH5/ICH5R) SMBus Controller (rev 02) 0000:01:02.0 VGA compatible controller: ATI Technologies Inc Rage XL (rev 27) 0000:02:00.0 PCI bridge: Intel Corp. PCI Bridge Hub A (rev 09) 0000:02:00.1 PIC: Intel Corp. PCI Bridge Hub I/OxAPIC Interrupt Controller A (rev 09) 0000:02:00.2 PCI bridge: Intel Corp. PCI Bridge Hub B (rev 09) 0000:02:00.3 PIC: Intel Corp. PCI Bridge Hub I/OxAPIC Interrupt Controller B (rev 09) 0000:04:01.0 Ethernet controller: Intel Corp. 82545EM Gigabit Ethernet Controller (Copper) (rev 01) 0000:04:03.0 SCSI storage controller: Adaptec AIC-7902 U320 (rev 03) 0000:04:03.1 SCSI storage controller: Adaptec AIC-7902 U320 (rev 03) 0000:07:00.0 InfiniBand: Mellanox Technology: Unknown device 6278 (rev a0) detailed lspci of e1000: 0000:04:01.0 Ethernet controller: Intel Corp. 82545EM Gigabit Ethernet Controller (Copper) (rev 01) Subsystem: Intel Corp. PRO/1000 MT Server Adapter Flags: bus master, 66MHz, medium devsel, latency 64, IRQ 209 Memory at fe2c0000 (64-bit, non-prefetchable) [size=128K] I/O ports at d480 [size=64] Capabilities: [dc] Power Management version 2 Capabilities: [e4] PCI-X non-bridge device. Capabilities: [f0] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable- 00: 86 80 0f 10 17 01 30 02 01 00 00 02 10 40 00 00 10: 04 00 2c fe 00 00 00 00 00 00 00 00 00 00 00 00 20: 81 d4 00 00 00 00 00 00 00 00 00 00 86 80 01 10 30: 00 00 00 00 dc 00 00 00 00 00 00 00 0b 01 ff 00 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 d0: 00 00 00 00 00 00 00 00 00 00 00 00 01 e4 22 00 e0: 00 00 00 00 07 f0 02 00 08 04 43 04 00 00 00 00 f0: 05 00 80 00 04 10 e0 fe 00 00 00 00 32 40 00 00 - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html