On 10.11.2014 12:47, Kenneth Johansson wrote: > So I have a problem that happens with 1-2 weeks interval in that the xhci driver confuses itself and thinks that the usb bus is overused or something. > > The thing is that this is an external usb 2 hub with 7 ports and all 7 is used for different devices. I do a suspend/resume once a day and thats it. > its the same devices on the hub but the USB driver for some reason decides that it no longer can allow the devices on the bus. > > 1. is there any way to reset the entire usb stack without rebooting?? I run 3.16 ubuntu kernel and I think usb is built in I at least can see any module named xhci. > > 2. what can be done to solve this ?? there must be some type of resource leak here as a reboot solves the problem and I have exactly the same usb devices that I use. > > 3. I also notice that we max out at about 30 devices and I think usb should be able to handle 127. > > 4. I noticed on a different computer that a usb sound card (5.1) was also getting the bandwidth error if I attached it to a usb3 hub that had only that device, it works if I remove the hub. > > 5. overall usb3 looks to be a bit "unpredictable" and if you google for this type of errors the advice is to downgrade to usb2. that do sound like the wrong thing to do unless the xhci hardware is that broken. is it ? or is this the driver that needs fixing. > > > > ----------------- > [65633.315419] usb 3-1.4.1: Product: USB Transfer Cable > [65633.315422] usb 3-1.4.1: Manufacturer: Prolific Technology Inc. > [65633.315607] xhci_hcd 0000:00:14.0: Not enough bandwidth on HS bus for newly activated TT. > [65633.315612] xhci_hcd 0000:00:14.0: Not enough bandwidth > [65633.315619] usb 3-1.4.1: can't set config #1, error -12 > --- > [65653.367865] xhci_hcd 0000:00:14.0: Not enough bandwidth on HS bus for newly activated TT. > [65653.367867] xhci_hcd 0000:00:14.0: Not enough bandwidth > [65653.367872] usb 3-1.2: can't set config #1, error -12 > > and so on. > -- > The xhci controller has a limit for max devices it can support, usually less than 127. 3.16 kernel and later should report "Max number of devices this xHCI host supports is %u.\n" when you reach the limit. I've got reports about bandwidth errors before, so far two different kinds, one is a context error which happends while allocating bandwith, and is not really a bandwidth issue. Then we also got real bandwith errors in cases when we really shouldn't ave them. This is one of the many issues I need to address after resolving other current issues (race in reset endpoint, reset device and stop endoint). Might be that it's just the driver that needs fixing, need to get my hands on it. Probably start with displaying more debug output when we hit bandwidth limits. -Mathias -- 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
