Re: APIC priorities, can they be changed?

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

On Thu, 15 Feb 2007, Mike Panetta wrote:

> I am not on the list (corperate email sucks) so please CC any replies to
> me.  Thanks.
>
> I am working on a project that has run in to what seems to be an
> interrupt priority problem.  We switched mainboards in our product and
> went from a system where the EHCI controller IRQ was of a fairly high
> priority to one where its the lowest in the system.  Now we cannot get
> the data off our USB device in time and we drop alot of data.  I was
> hoping someone here may have a simple(ish) solution to the problem.
>
> I have seen the preempt patches, but they touch a lot of files, and we
> have gone through testing with the 2.6.16.19 kernel and do not wish to
> change, and we cannot find a version of the patch for this kernel. Is
> there something smaller/simpler I can do?  My understanding is the
> priority in the APIC is set in software via the interrupt vector number
> (higher numbers have lower priority) is this true?  If so, how hard
> would it be for me to just change the vector numbers around?
>
> Ideally I would love to switch to the 2.6.20 kernel and use the preempt
> patch, but I doubt we have the time for that.
>
> Thanks,
> Mike

Can't you muck with the BIOS settings? That's where the primary
hardware gets 'connected'.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.61 BogoMips).
New book: http://www.AbominableFirebug.com/
_


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