sio / puc wedging on both -current and -stable

[Bruce Evans]

Long ago, On Thu, 3 Jun 2004, Mike Tancsa wrote:

> Just a quick recap.  I can fairly easily trigger an interrupt storm on
> these machines with USB enabled in the BIOS.  If I disable it, I dont have
> a problem and all works well.... However, what I accidently came across
> today, was that if I load the USB drivers as a kld, I can *not* wedge the
> machine.  Note the bottom of the following diff

I can now explain this.  When usb is in the kernel proper, it normally
gets the interrupt first and exposes bugs in sio (see other mail --
there is a conflict but sio ignores the error).  When usb is in a
module, sio normally gets the interrupt first.  There is again a
conflict but usb doesn't ignore the error.

> diff dmesg.kld dmesg.static
>
> < uhci2: <Intel 82801DB (ICH4) USB controller USB-C> port 0xb400-0xb41f irq
> 12 at device 29.2 on pci0
> < uhci2: Could not allocate irq
> < device_probe_and_attach: uhci2 attach returned 6
> < uhci2: <Intel 82801DB (ICH4) USB controller USB-C> port 0xb400-0xb41f irq
> 12 at device 29.2 on pci0
> < uhci2: Could not allocate irq
> < device_probe_and_attach: uhci2 attach returned 6

This shows uhci2 not ignoring the error.

Bruce