The following reply was made to PR usb/156596; it has been noted by GNATS.
From: Colin Percival <cperc...@freebsd.org>
To: Hans Petter Selasky <hsela...@c2i.net>
Cc: "bug-follo...@freebsd.org" <bug-follo...@freebsd.org>
Subject: Re: usb/156596: [ehci] Extremely high interrupt rate on ehci/uhci
IRQ16 80% cpu utilization on CPU0
Date: Sun, 10 Jul 2011 18:30:22 -0700
On 07/09/11 02:07, Hans Petter Selasky wrote:
> Have you tried to set any of these quirks:
> hw.usb.ehci.lostintrbug: 0
> hw.usb.ehci.iaadbug: 0
Yes. Neither has any effect. (At least, not when I set them via sysctl; I
could try setting them as loader tunables if you think that would make a
> The attached patch seems to fix the problem while not breaking anything on
> my laptop.
Key words, "seems to". On further use I've found that my change didn't make
any difference; it was just a coincidence that the problem temporarily went
away at that time.
However, I've managed (I think!) to figure out what's triggering this: The
IRQ flood starts when the laptop battery is recharging. Letting the battery
run down for a couple hours and then plugging in AC power has 100% consistently
triggered this; but if the battery is already fully charged when FreeBSD boots
I don't get the IRQ flood.
Hans Petter Selasky wrote:
> Try the attached patch and report back. The EHCI should never generate more
> than 8000 IRQ/s second, so this clearly indicates a Hardware Problem.
No change, I'm afraid.
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