> > Sorry ... I thought he had posted lcpci showing a NEC controller > > with EHCI *and* OHCI. > > It is a NEC controller with both. But I have 1.0 hub plugged in with > three 1.0 devices in it. The 1.0 hub causes the OHCI controller in > the NEC to be used. > > I have had even worse luck trying to get three USB audio devices > working on 2.0. That NEC chip is a single-TT EHCI implementation.
Actually it's a NEC chip with a zero-TT implementation. ;) I forget why our high speed root hubs lie about having a TT. They probably don't need to do that, except for the ones that don't have companion controllers. Like the silicon using the IP from ARC, Mentor, and so on. > USB plug and play sure doesn't work very well with three audio > devices. I didn't catch those details. What do you mean by that? Do they not enumerate? Do their drivers not get loaded? Is some userspace setup missing? Or do the drivers misbehave? Disconnecting isn't what I'd call a PNP issue. > I'd like to be able to use six with the NSLU2, it has enough > CPU power. But I can't even get three to work reliably. It might not have enough DMA capacity; there are other issues that can affect system capability... > So if I get a 2.0 hub with multi-TT, and plug it into the NEC chip > whose EHCI hub is only single-TT, does this have a chance of working? It has a chance of working, yes. Only one TT is ever involved with a given full or low speed device, and it'll be found in the nearest upstream hub running at full speed. While you're connecting to the root hub, the nearest such hub is OHCI and no TT matters. If you connect a multi-TT hub, that's what will matter. > What I need are 2.0 audio devices but they don't appear to exist. Some exist, but they're not common. ISTR they were geared for sound card replacement -- and thus needed lots of channels. Normally audio doesn't need much bandwidth, so there's no point in paying any of the extra costs implied by high speed support. - Dave - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
