Re: PCI Interrupt

["linux-os \(Dick Johnson\)" <linux-os@analogic.com>]

On Tue, 18 Sep 2007 Duncan.Perrett@elekta.com wrote:

> The driver already does that ...
>
> result =
>        request_irq(irq, can_pci_interrupt, SA_INTERRUPT | SA_SHIRQ,
>                    pDevice->au8IrqName, pDevice);
>
>
> Any other ideas?
>
> Duncan
>
>
>             "linux-os \(Dick
>             Johnson\)"
>             <linux-os@analogi                                          To
>             c.com>                    <Duncan.Perrett@elekta.com>
>                                                                        cc
>             18/09/2007 14:57          "Linux kernel"
>                                       <linux-kernel@vger.kernel.org>
>                                                                   Subject
>             Please respond to         Re: PCI Interrupt
>             "linux-os \(Dick
>                Johnson\)"
>             <linux-os@analogi
>                  c.com>
>
> On Tue, 18 Sep 2007 Duncan.Perrett@elekta.com wrote:
>
>>
>> I have a CAN PCI card installed on my Ubuntu box.
>> I understand that PCI interrupts should be level rather than edge
>> triggered.
>>
>> The output of cat /proc/interrupts is :-
>>
>>           CPU0
>>  0:    1614601    IO-APIC-edge  timer
>>  1:        164    IO-APIC-edge  i8042
>>  8:          3    IO-APIC-edge  rtc
>>  9:          1   IO-APIC-level  acpi
>> 12:          0    IO-APIC-edge  CAN-ACx-PCI_01
>> 14:      65786    IO-APIC-edge  ide0
>> 169:       3220   IO-APIC-level  eth0, i915@pci:0000:00:02.0
>> 177:      46459   IO-APIC-level  eth1
>> 209:          0   IO-APIC-level  uhci_hcd:usb3, eth2
>> 217:          2   IO-APIC-level  uhci_hcd:usb1, ehci_hcd:usb4
>> 225:        697   IO-APIC-level  uhci_hcd:usb2
>> NMI:          0
>> LOC:    1614399
>> ERR:          0
>> MIS:          0
>>
>> You see that irq 12 CAN-ACx-PCI_01 is edge triggered.
>> Is there any way of forcing the BIOS to see the interrupt as a
>> level-triggered one?
>
> It's done in the driver. IRQ12 can be shared, so the driver
> needs to request the IRQ as a shared interrupt.
>
>
> Cheers,
> Dick Johnson
> Penguin : Linux version 2.6.22.1 on an i686 machine (5588.30 BogoMips).
> My book : http://www.AbominableFirebug.com/
> _

Okay, then in the BIOS, make sure that IRQ12 is not assigned to
a specific device. In other words, set it to PnP (if available).
As you well know, PCI requires sharable interrupts and edges
are not sharable so something is broken. As a last resort,
move your PCI board to abother slot which should pick up another
interrupt, which may not be broken. If that doesn't work, see
if a new BIOS is available for download.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.22.1 on an i686 machine (5588.30 BogoMips).
My book : http://www.AbominableFirebug.com/
_


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