[mythtv-users] OT: kernel disabling IRQ#7 (Sound Stops working)

[Joe Votour]

IRQ7 is usually that of the parallel (a.k.a. printer)
port.  If the sound card is taking IRQ7, then either
there's no printer port on the machine, or something
is messed up with IRQ sharing (and I'd bet on the
latter).

If the sound card can't be moved away from IRQ7, then
try disabling the printer port on the motherboard, so
that IRQ7 is freed up.

I have seen some messages from the kernel about
spurious interrupts on IRQ7 before - this is just
apparently due to the wiring of the parallel port, and
they haven't caused any problems in the past, at least
not for me.

-- Joe

--- Mark Knecht <markknecht at gmail.com> wrote:

> Hi,
> First, let's be sure that the sound card is on IRQ7
> 
> cat /proc/interrupts
> 
> If IRQ7 is the correct interrupt then typical reason
> that interrupts
> will get disabled is that the interrupt controller
> is receiving
> spurious interrupts on that channel. The interrupt
> happens, the
> interrupt service routine goes to read all the chips
> on that IRQ and
> finds that no chip says it generated the interrupt.
> Normally after a
> few of these the system will shut down the channel
> and interrupts for
> all devices on that channel are hosed.
> 
> There are typically a few normal reasons for this
> stuff:
> 
> 1) The system has some design problem. Internal
> noise messes with IRQ
> line on the motherboard.
> 
> 2) A chip is bad or going bad. This could be the
> chipset of the sound card.
> 
> Possible solutions:
> 
> a) If the sound card is sharing and interrupt with
> other cards or
> devices then try to isolate the sound card on it's
> own interrupt. Try
> placing it in a different PCI slot.
> 
> b) If this is an onboard sound ship then ensure that
> no other decide
> you have control over shares the interrupt. I.e. -
> if the sound card
> is sharing an interrupt with a PCI Ethernet adapter
> then try moving
> the NIC to another slot.
> 
> c) If the above ideas don't work and this is a PCI
> device then try
> another sound card
> 
> d) It is possible hat the problem is on the
> motherboard itself. The
> solution for that is not pretty.
> 
> e) All of this can be caused by bad programming of
> the chipset.
> Investigate other kernels or distros for this sort
> of problem &
> potential solutions. Some distros add patches, some
> don't. Try a
> kernel.org kernel instead of a prepackaged kernel.
> 
>    Good luck. I've struggled through this a couple
> of times over the
> years. There are usually solutions but they are not
> (in my experience)
> always easy to find.
> 
> Cheers,
> Mark
> 
> On 7/11/05, Noel Murphy <bnmurphy at rogers.com> wrote:
> > Hello,
> > 
> > I realize this isn't mythtv specific, however it
> is happening on my
> > box which is used specifically for mythtv.
> > 
> > I have a weird issue where when I don't use the
> machine for awhile
> > (say the whole weekend because I'm gone to the
> cottage) when I
> > return, I have a Knotify message up on the screen
> telling me that the
> > kernel has disabled IRQ #7 (Which I believe is the
> interrupt for the
> > sound card). Then, when I try to watch any
> recordings or live tv, I
> > get no sound.
> > 
> > A reboot always fixes the problem (until the
> following weekend when I
> > go away again).
> > 
> > Anyone know why this is happening????
> > 
> > Noel
> > 
> > 
> > 
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users at mythtv.org
> >
>
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> > 
> > 
> >
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>
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> 


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