On Wednesday 19 January 2005 9:51 am, Jesse Barnes wrote: > On Tuesday, January 18, 2005 5:39 pm, David Brownell wrote: > > > 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. > > 66: 0 4407 0 0 SN hub ohci_hcd > 67: 0 517 0 0 SN hub ohci_hcd, > ehci > > [Above is after loading ohci first--a working setup. If I load ehci first, > irq 66 spins out of control and is eventually shut off by the kernel because > of too many IRQ_NONE returns.]
What happens when you load EHCI _only_ ? Normally loading that driver won't cause any interrupts at all, until some device is connected. 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.) > How is this supposed to work? Perfectly! Or at least as far as a small flotilla of penguins can achieve such a thing before taking a break for some pickled herring! :) > I've just tested again and things work ok as > long as I load ohci first. The interrupts seem to be getting assigned > correctly by the BIOS (there are supposed to be two of them, right?), but it > looks like if ehci registers its interrupt handler first, it just returns > IRQ_NONE, causing hcd_irq to not handle irq 66, which is apparently the usb > 1.1 ohci controller. Maybe you have issues with IRQ sharing? You said this was a NEC card; and those work fine for most folk. I've got one in a K7 box here, and it doesn't have those init problems. Two OHCI controllers, one EHCI; IRQ sharing as arranged by your BIOS, typically the card puts each controller on a separate IRQ line but the PCI IRQ routing ends up sharing things. (On that box I've got two EHCIs and six OHCIs, lots of sharing, no problems.) - Dave > > Thanks, > Jesse > ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
