Re: Interrupt latency problems

From: Paul Richards <paul_at_freebsd-services.com>
Date: 12 May 2003 02:41:04 +0100
On Mon, 2003-05-12 at 01:25, Andrew Gallatin wrote:
> Paul Richards writes:
> 
>  > > : 
>  > > : I get boatloads of these, they stream past continuously.
>  > > : 
>  > > : ACPI-0448: *** Error: AcpiEvGpeDispatch: No handler or method for
>  > > : GPE[0], disabling event
> 
> <...>
> 
>  > No, it's a Supermicro DLE, with 2 P3-800 processors.
>  > 
> 
> 
> I've complained about these messages on my old DLE at least 3 times.
> Nobody ever helped.
> 
> I found that on my old DLE, the messages will stop if you unplug the
> cable to the onboard fxp0 interface.  They seem to happen each time
> the device interrupts the host.  These messages are a total DOS on a
> server with a serial console, so I wouldn't be surprised if they
> caused a perceptable slowdown on a box with a graphics head.

Hmm, this is all starting to sound very familiar, because the fxp
interface sometime stops responding as well and I have to reboot to make
it start working again, even unloading and reloading the module doesn't
help which points towards the hardware getting jammed and interrupts not
happening.

I wonder if something triggers an ACPI event when a packet arrives and
that causes all these messages to be generated which causes a lock to be
long enough for an fxp interrupt to be missed, which then confuses the
fxp driver so it never clears it and leaves the card jammed. Maybe it's
got something to do with ACPI watching the interrupt to wake up from
suspend when a network packet arrives. Yhis is total speculation but it
sounds plausible on paper :-)

> Good luck getting an ACPI developer interested in it.  I had no luck.
> My advice is to just disable ACPI & forget about using it.

Unfortunately if I disable acpi completely things are worse. The
symptoms are a lot like a switch that isn't debounced, i.e. random
multiples of keystrokes appear.

-- 
Paul Richards <paul_at_freebsd-services.com>
Received on Sun May 11 2003 - 16:45:55 UTC

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