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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 19:42:53
Message-ID: 200501191142.53690.jbarnes () sgi ! com
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On Wednesday, January 19, 2005 11:20 am, David Brownell wrote:
> What happens when you load EHCI _only_ ?  Normally loading that driver
> won't cause any interrupts at all, until some device is connected.

Yep, that's what happens.  I have a USB 1.1 kbd plugged into the 2.0 port and 
I don't see any interrupts:

 67:          0          0          0          0          SN hub  ehci_hcd

> Then there are basically two paths:  (a) it's a full/low speed device,
> handled by OHCI (or on some cards, UHCI); or (b) it's a high speed device,
> handled by EHCI.  To test the latter, I suggest you grab a USB 2.0 hub;
> the slim 4 port ones using Mini-B connectors, just a bit bigger than a
> credit card, are the most featureful.  (They have Cypress chips that have
> a transaction translator on each port; which means you can hook up a lot
> more full and low speed devices downstream.  All controlled by EHCI.)

Ok, that's worth a try to make sure EHCI is working at all (I suspect it is).

> Maybe you have issues with IRQ sharing?

Quite possible since it looks like the EHCI chip shares an IRQ with one of the 
OHCI chips.  I'll take a look at that.

Thanks,
Jesse


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