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List:       linux-usb-devel
Subject:    Re: [linux-usb-devel] EHCI & OHCI interrupt weirdness
From:       Jesse Barnes <jbarnes () sgi ! com>
Date:       2005-01-19 17:01:10
Message-ID: 200501190901.10262.jbarnes () sgi ! com
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On Tuesday, January 18, 2005 5:39 pm, David Brownell wrote:
> Your BIOS doesn't like our kernel.  :(
>
> Try booting with the kernel "usb-handoff" parameter; that helps
> some folk who run into this kind of problem.  At least, when the
> issue is the BIOS actually _using_ that controller in some way
> (like enabling "legacy" mode keyboard/mouse handling in hardware
> or having a built-in USB driver itself).

Hm, the BIOS on this particular machine is totally unaware of USB devices 
(i.e. no kbd/mouse driver at all, doesn't attach to USB devices, etc.).

> Though your messages didn't show any signs of needing to handshake
> with the BIOS; so the other "usual" issue is the IRQ setup being
> goofed, also very often caused by disagreements between BIOS tables
> and Linux.

That may be... it certainly appears to be IRQ related.  If I load the ohci 
driver by itself, I can use the kbd/mouse on this machine just fine.  It's 
when I load the ehci driver that I start to see problems.  I'll test a bit 
more thoroughly today with all the ports and such.

> > Does it matter which driver I load first, ehci or ohci?
>
> I recommend EHCI first, to minimize resetting of USB devices during
> initialization and simplify the PM resume scenarios.  Other than
> that issue, it's not supposed to matter.

I *think* when I tested yesterday things worked ok if I loaded ohci first, 
which would indicate that maybe something isn't right in the ehci interrupt 
handler?  Like I said, I'll test some more today.

Thanks,
Jesse


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