Messages in this thread | | | From | Robert Hancock <> | Subject | Re: Different IRQ mapping from 2.6.27->2.6.28? | Date | Tue, 30 Dec 2008 11:27:32 -0600 |
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Justin Piszcz wrote: > Had a quick question, prior to 2.6.28 the 915 controller always shared > irq 16 > with the 3ware controller and possibly usb. > > $ cat /proc/interrupts > CPU0 CPU1 CPU2 CPU3 > 0: 829 0 0 0 IO-APIC-edge timer > 1: 2 0 0 0 IO-APIC-edge i8042 > 9: 0 0 0 0 IO-APIC-fasteoi acpi > 12: 4 0 0 0 IO-APIC-edge i8042 > 16: 426034 626134 1351627 1342735 IO-APIC-fasteoi > 3w-9xxx, uhci_hcd:usb3 > 17: 0 0 0 0 IO-APIC-fasteoi > pata_marvell > 18: 0 0 0 0 IO-APIC-fasteoi > ehci_hcd:usb1, uhci_hcd:usb7 > 19: 1375 341 0 0 IO-APIC-fasteoi > ohci1394, uhci_hcd:usb6 > 21: 297232 2133384 741689 1238741 IO-APIC-fasteoi > uhci_hcd:usb4, eth1 > 22: 205140 294852 1063046 234799 IO-APIC-fasteoi HDA > Intel, eth2 > 23: 332083 3050489 0 0 IO-APIC-fasteoi > ehci_hcd:usb2, uhci_hcd:usb5 > 375: 376161 1019158 163030 68967 PCI-MSI-edge ahci > 376: 56580 2533694 390596 2673511 PCI-MSI-edge eth0 > 377: 0 0 0 0 PCI-MSI-edge > i915@pci:0000:00:02.0 > NMI: 0 0 0 0 Non-maskable interrupts > LOC: 213813409 215685728 213463846 214264243 Local timer interrupts > RES: 62066 64812 41593 54593 Rescheduling interrupts > CAL: 1425 1476 1445 606 Function call interrupts > TLB: 96105 94258 117036 107468 TLB shootdowns > TRM: 0 0 0 0 Thermal event interrupts > THR: 0 0 0 0 Threshold APIC > interrupts > SPU: 0 0 0 0 Spurious interrupts > ERR: 0 > MIS: 0 > > I was curious if this change had something to do with it? > > From: > http://kernelnewbies.org/LinuxChanges?action=print > i915: Add support for MSI and interrupt mitigation. (commit), disable > MSI on GM965 (errata says it doesn't work) (commit) > > Are there any pros or cons having the device mapped to the PCI-MSI-edge vs. > sitting on a regular IRQ? I am trying to understand the differences here, > thanks!
It's better to have devices on MSI interrupts because the interrupt source is always unambiguous (interrupts are never shared), among a few other reasons..
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