On 21/11/09 23:28, Alan Stern wrote: > On Sat, 21 Nov 2009, Simon Arlott wrote: >> It just suddenly stopped at "usb 4-2.4.4.4: new full speed USB >> device using ohci_hcd and address 107". > > If all those intermediate hubs are bus-powered, that's not at all > surprising. They are, and they all pretend to be self-powered, but it shouldn't cause a deadlock situation. I couldn't resolve it even by unplugging all devices from that host controller. >> With so many hubs all the suspend/resume cycles cause numerous >> delayed reactions... if 4-2.4.4.4 is an USB hub (4 hubs in series >> connected to the host), should I be able to connect a device to it >> or have I reached the limit already? > > You are allowed to have up to six links in the chain, that is, a device > plugged into five hubs (provided you don't violate the rule about no > plugging one bus-powered hub into another). I keep seeing conflicting information, sometimes claiming that the host itself counts within the "five" hubs rule. Although it does look like there's a lack of voltage to power the end device at that distance. > This sort of thing is explained very clearly in the USB 2.0 > specification, freely available at www.usb.org. It's got lots of > interesting and useful information; you might enjoy looking through it. They really need to fix their webserver... the download speed started at 250KB/s and is now at 3-4KB/s. -- Simon Arlott -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
