Re: [LAU] irq sharing

--- On Tue, 8/24/10, David Santamauro <david.santamauro@email-addr-hidden> wrote:

> From: David Santamauro <david.santamauro@email-addr-hidden>
> Subject: Re: [LAU] irq sharing
> To: "Mark Knecht" <markknecht@email-addr-hidden>
> Cc: "LAU" <linux-audio-user@email-addr-hidden>
> Date: Tuesday, August 24, 2010, 11:55 AM
> On Tue, 24 Aug 2010 08:30:39 -0700
> Mark Knecht <markknecht@email-addr-hidden>
> wrote:
>
> > On Tue, Aug 24, 2010 at 8:13 AM, David Santamauro
> > <david.santamauro@email-addr-hidden>
> wrote:
> > >
> > > Mark,
> > >
> > >
> > > On Tue, 24 Aug 2010 06:54:30 -0700
> > > Mark Knecht <markknecht@email-addr-hidden>
> wrote:
> > >
> > >> On Tue, Aug 24, 2010 at 5:10 AM, David
> Santamauro
> > >> <david.santamauro@email-addr-hidden>
> wrote:
> > >> >
> > >> > Hi,
> > >> >
> > >> >
> > >> > Is there a way to forcibly assign
> ICE1712 to another IRQ? I just
> > >> > want to test the theory.
> > >> >
> > >>
> > >> IRQ's and their numbering are physical
> things. Their assignment is
> > >> made, fundamentally, when the motherboard is
> designed and is
> > >> hardwired based on the PC board traces. You
> cannot change those.
> > >>
> > >> For desktop machines the control you do have
> is to move PCI
> > >> devices to different PCI slots. Asus
> motherboards are usually
> > >> pretty good about calling out what slots
> share interrupts with
> > >> other devices. Check your MB manual.
> > >>
> > >> If you don't have a manual use your eyes and
> think about the whole
> > >> IRQ list. (Not just the part you showed.)
> Look for another PCI
> > >> card that seems to be on an interrupt by
> itself and then switch
> > >> that card with your sound card.
> > >
> > > Manual says PCI at irq 20.
> > >
> > >>
> > >> For USB devices, if you have multiple USB
> controllers and _if_ they
> > >> use different IRQs, then you may be able to
> choose a different
> > >> controller by choosing a different USB
> connector to plug into. Move
> > >> your USB devices if this appears to be true
> about your motherboard.
> > >> (It is on many of mine...)
> > >>
> > >> Note that sharing IRQs with a USB controller
> isn't necessarily
> > >> bad. It depends on what sort of USB device is
> attached, how its
> > >> driver is written, and how many interrupts it
> generates. However,
> > >> all things being equal, it's better if
> everything is completely
> > >> separated as that allows very little
> interaction.
> > >
> > > thanks for the time. I only have one PCI slot,
> but 3 empty PCI-x
> > > slots.
> > >
> > > I basically unplugged all USB devices as well as
> shut off both
> > > network interfaces and on board audio interface
> in the bios and the
> > > noise persists ...
> > >
> > > Not sure what to try next, this was a
> shot-in-the-dark.
> > >
> > > David
> >
> > David,
> >    Well, at first blush that implies to me
> this has nothing to do with
> > interrupts. Is the any card good? Have you tried it in
> another system?
>
> the card works fine on the same hardware under 64-bit
> windows7. I'm
> trying to get it working 100% in fedora 12 64-bit with an
> rt-kernel
> (multi-os machine). I agree, interrupts are probably not
> the issue.
>
> Last time I was fiddling with this problem I had suspected
> 64-bit
> linux drivers as it works in the 32-bit machine I have.
>
> >    This was a long time ago in my chip
> design architect history but I
> > helped write one of the early versions of the PCI-x
> spec for bridging
> > devices. IIRC PCI-x host controllers were supposed to
> correctly handle
> > both 32-bit and 64-bit PCI cards when plugged into
> those slots so
> > (according to the original spec written maybe 12 years
> ago) if your
> > card physically plugs into whatever connectors your MB
> provides it
> > should work. (I.e. - PCI-x slows down to become PCI.)
> However if you
> > had any PCI-x cards they would slow down also. Not a
> problem in your
> > case it seems.
> >
> >    Obviously we don't want to damage
> anything so I'd check your MB
> > manual on this, as well as looking at any BIOS for any
> settings or
> > clues about allowing PCI cards in PCI-x slots. You'll
> find a
> > supporting position here:
> >
> > http://en.wikipedia.org/wiki/Pci-x
>
> I read that as well, but my MB pci-x slots are (apparently)
> backwards
> (pardon my ignorance)
>
> see page 7
> http://www.tyan.com/manuals/m_s5396_120.pdf
>
> ... backwards, meaning, I'd have to stick the card in
> backwards.
>

wow, how backward! (pun intended :)
Would a PCI ribbon extender like this one help ?

http://www.plinkusa.net/webR1PCI1-1R.htm

I know you can find PCI risers of various length. I used to use one in my mini ITX multimedia server some long time ago. Don't remember the specs now but that should allow you to twist things back to a normal position (hopefully).

J.

> David
>
> _______________________________________________
> Linux-audio-user mailing list
> Linux-audio-user@email-addr-hidden
> http://lists.linuxaudio.org/listinfo/linux-audio-user
>

      
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user
Received on Fri Aug 27 04:15:04 2010