Chanadra, I've forwarded your question linux-pci mailing list. The answer is not a simple one and I'm not aware of any simple explanations since it's a combination of "generic" and x86 dependent code that assigns the IRQs. Perhaps someone else can direct you appropriately. hth, grant ----- Forwarded message from chanadra gorentla <chandragorentla@xxxxxxxxxxx> ----- X-Spam-Checker-Version: SpamAssassin 3.1.4 (2006-07-26) on colo.lackof.org X-Spam-Level: ***** X-Spam-Status: No, score=5.2 required=5.5 tests=BAYES_50,FORGED_RCVD_HELO, HTML_40_50,HTML_MESSAGE autolearn=no version=3.1.4 X-Greylist: delayed 317 seconds by postgrey-1.27 at palinux; Wed, 28 May 2008 23:10:47 MDT X-Originating-IP: [203.92.59.3] From: chanadra gorentla <chandragorentla@xxxxxxxxxxx> To: grundler@xxxxxxxxxxxxxxxx, greg@xxxxxxxxx Subject: PCI_INTERRUPT_LINE - GSI - IRQ on a x86 SMP machine X-OriginalArrivalTime: 29 May 2008 05:05:14.0253 (UTC) FILETIME=[9428BBD0:01C8C149] X-Virus-Scanned: by amavisd-new-20030616-p10 (Debian) at lackof.org Hello Grant and Greg, Sorry for sending this directly to you. The mailing list at '' seems to be closed. This is about translation of PCI_INTERRUPT_LINE to IRQ on a x86 SMP machine. I am curious about how this happens. For example I am seeing 0xB in the PCI_INTERRUPT_LINE register of a PCI board I have; The GSI (global system interrupt) for this board is 16; The IRQ assigned for this board is 169. Can you please suggest some links (documents/source code files etc. I tried - http://lxr.linux.no/ - this did not help me) where I can find how '0xb' of PCI interrupt line register contents is translated to the IRQ # 169? Thanks in advance, chandra ------------------------------- Following is the part of the '/var/log/message'. May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:01.0[A] -> GSI 16 (level, low) -> IRQ 169 May 28 17:44:25 RHL-4-Dev rc: Starting lm_sensors: succeeded May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1c.0[A] -> GSI 17 (level, low) -> IRQ 177 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1d.0[A] -> GSI 23 (level, low) -> IRQ 185 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1d.1[B] -> GSI 19 (level, low) -> IRQ 193 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1d.2[C] -> GSI 18 (level, low) -> IRQ 201 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1d.3[D] -> GSI 16 (level, low) -> IRQ 169 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1d.7[A] -> GSI 23 (level, low) -> IRQ 185 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1f.1[A] -> GSI 18 (level, low) -> IRQ 201 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:00:1f.3[B] -> GSI 19 (level, low) -> IRQ 193 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:02:01.0[A] -> GSI 24 (level, low) -> IRQ 209 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:03:00.0[A] -> GSI 16 (level, low) -> IRQ 169 <--- I am referring to this. May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:0a:01.0[A] -> GSI 20 (level, low) -> IRQ 217 May 28 17:44:25 RHL-4-Dev kernel: ACPI: PCI interrupt 0000:0a:03.0[A] -> GSI 21 (level, low) -> IRQ 225 . . . Following is the 'lspci -x' output for the board I am referring. [root@RHL-4-Dev ~]# lspci -x . . . 00: d8 12 30 e1 07 01 10 00 01 00 80 07 08 00 00 00 10: 00 00 70 dd 01 50 00 00 00 00 60 dd 00 00 50 dd 20: 00 00 40 dd 00 00 00 00 00 00 00 00 b6 12 68 65 30: 00 00 00 00 b0 00 00 00 00 00 00 00 0b 01 00 00 . . . [root@RHL-4-Dev ~]# cat /proc/interrupts CPU0 CPU1 0: 119886 80025 IO-APIC-edge timer 1: 11 0 IO-APIC-edge i8042 8: 1 0 IO-APIC-edge rtc 9: 0 0 IO-APIC-level acpi 14: 6245 2057 IO-APIC-edge ide0 169: 1 0 IO-APIC-level cg6k <--- This is the board I am referring 185: 0 0 IO-APIC-level ehci_hcd 209: 3 0 IO-APIC-level cg6k 217: 493 0 IO-APIC-level eth0 NMI: 0 0 LOC: 199714 199713 ERR: 0 MIS: 0 ----- End forwarded message ----- -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
