From: Robert Hancock <hancockr@shaw.ca>
To: Lapo TIN <lapolapolapo@tin.it>
Cc: linux-smp@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: smp and irq conflict
Date: Thu, 01 Feb 2007 17:29:36 -0600 [thread overview]
Message-ID: <45C277E0.2040604@shaw.ca> (raw)
In-Reply-To: <fa.bd33YMixT9/jJwHfbD/DebGgVXs@ifi.uio.no>
Lapo TIN wrote:
> Dear all,
> I have a problem with IRQs.
>
> My pc has a CPU PentiumD945 (dual core) and a 2.6.19smp kernel.
> I have two video acquisition board (four bt8t8 each) in the only two pci
> slots of my motherboard. Thus I have a total of 8 bttv modules that are
> working together, and the /proc/interrupts is as follows:
> # cat /proc/interrupts
> CPU0 CPU1
> 0: 13575 0 IO-APIC-edge timer
> 1: 2 0 IO-APIC-edge i8042
> 4: 11 0 IO-APIC-edge serial
> 8: 1 0 IO-APIC-edge rtc
> 9: 0 0 IO-APIC-fasteoi acpi
> 12: 4 0 IO-APIC-edge i8042
> 14: 22286 0 IO-APIC-edge ide0
> 17: 7073 2097 IO-APIC-fasteoi uhci_hcd:usb5, eth0
> 18: 2525 0 IO-APIC-fasteoi bttv0, bttv7
> 19: 2829 0 IO-APIC-fasteoi bttv1, bttv4
> 20: 2526 0 IO-APIC-fasteoi bttv2, bttv5
> 21: 2226 0 IO-APIC-fasteoi bttv3, bttv6
> 22: 2 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb4
> 23: 86 0 IO-APIC-fasteoi uhci_hcd:usb2
> 24: 0 0 IO-APIC-fasteoi uhci_hcd:usb3
> NMI: 0 0
> LOC: 13484 13502
> ERR: 0
> MIS: 0
> You can see that IRQ18 is shared between bttv0 and bttv7, IRQ19 between
> bttv1 and bttv4 and so on.
>
> Sometimes it crashes. It seems a matter of conflict in IRQ.
> With only one video board everything is ok, but with two, they shared irq
> and something goes wrong...
> How can I tell to the kernel to not to share the IRQ for these boards ?
> I think (I don't know if I'm right) that this could be the problem.
Usually the IRQ routing is hard-wired on the motherboard, so there's no
way to avoid the devices sharing IRQs. Unless the driver is badly buggy
this should not cause problems anyway.
What kind of video bit rate are you capturing? 8 video capture chips is
a pretty heavy load on the PCI bus, maybe something just gets overwhelmed?
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/
next parent reply other threads:[~2007-02-01 23:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <fa.bd33YMixT9/jJwHfbD/DebGgVXs@ifi.uio.no>
2007-02-01 23:29 ` Robert Hancock [this message]
2007-02-02 0:04 ` smp and irq conflict Lapo TIN
2007-02-02 0:59 ` Robert Hancock
2007-02-02 11:08 ` Erik Mouw
2007-02-14 17:59 ` Manu Abraham
2007-02-01 17:46 Lapo TIN
2007-02-02 4:32 ` Andrew Morton
2007-02-02 5:22 ` Len Brown
2007-02-02 14:52 ` Bill Davidsen
2007-02-05 10:33 ` Benny Amorsen
2007-02-14 16:45 ` Bill Davidsen
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