On Tue, 6 Dec 2011, Sancho Dauskardt wrote: > On 06.12.2011 09:40, Andiry Xu wrote: > > On 12/06/2011 01:19 AM, Sancho Dauskardt wrote: > > > > [...] > > There is a known issue on SB700 with usb hub, see commit b09bc6cb "USB: > > fix SB700 usb subsystem hang bug". > > > > Other than that, I'm not aware of any SB700 EHCI issues involved with > > USB hub. > > > > > Yes, we've gone through all the eratta and tried around, but thanks. > > What also really bugs me, is that the hub between the root-hub and > usb-storage device really makes a difference. > Monitoring the link between hub and root hub never showed any bad > packets but still there is packet loss upstream with the hub and none > without. Did you try monitoring the link between the hub and the device? Did the packets look the same from that viewpoint? > Could the hub be changing the timing in some minor way that breaks the > root hub ? I don't know about changing the timing. It certainly could change the other electrical characteristics (voltage and so on). You may have mentioned this before, but I don't remember: Did you try using other brands of hubs? > Back from the uhci days i remeber all sorts of strange "babble" issues. > Do ehci's report this properly ? Yes. > Is there any way of creating a long delay between acesses to different > devices ? i.e. some sort of scheduling pause. No. That's all handled automatically by the controller hardware. Alan Stern -- 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
