Thanks for replying Alan. I really appreciate it. You asked what I was hoping to do. I have a six camera system that crashes regularly forcing a reboot. I'm hoping to get more stability. It's possible that the failure is software and not hardware or kernel, but at any rate I'd like to know what the issue really is. Will this cable work for HCI debug? http://www.datapro.net/products/usb-3-0-super-speed-a-a-debugging-cable.html Will any crossover cable work? I thought HCI debug had disappeared from the kernel because there is no option under debugging to enable the HCI debugger like there is for kbd and serial. Sorry the dmesg was so verbose. I've been experimenting with the hardware and was able to isolate the failure to a single port. Changing cameras or hubs didn't make a difference. At the moment (with kernel 3.5.2) This particular right side xHCI port will not accept the USB hub. Here is the output of dmesg for the port when the HUB is plugged in. Note: the cameras are enabled when I plug it in, but shutting them off or leaving the hub disconnected does not make any difference. The hub is not working. [ 4855.820204] usb 1-1: new high-speed USB device number 46 using xhci_hcd [ 4855.964916] usb 1-1: New USB device found, idVendor=05e3, idProduct=0610 [ 4855.964919] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 4855.964920] usb 1-1: Product: USB2.0 Hub [ 4855.964921] usb 1-1: Manufacturer: GenesysLogic [ 4855.965769] hub 1-1:1.0: USB hub found [ 4855.966348] hub 1-1:1.0: 4 ports detected [ 4858.173486] usb 2-1: Device not responding to setup address. [ 4858.383424] usb 2-1: Device not responding to setup address. [ 4858.590051] usb 2-1: device not accepting address 19, error -71 What can I do from here, without kgdb access? Thanks again, Brian On 05/16/16 12:52, Alan Stern wrote: > On Mon, 16 May 2016, Brian T. McKee wrote: > >> I sent a message to the group yesterday, but I suspect it was too big >> for it's own good and didn't make it to the list. > It did; I saw it. > >> I'm attempting to debug a USB problem where multiple UVC camera causes >> the USB driver to crash and shut down. All *HCI devices stop working. > If you could post a dmesg log showing how this happens, it might help. > >> I managed to get a USB serial port up and running on my laptop and >> connect it to an old machine with a built in serial port, as an attempt >> to get KGDB running, but alas, KGDB does not recognize /dev/ttyUSB0 as a >> valid device. >> >> It looks like KGDB does not support the EHCI debug cable anymore, > It should. If it doesn't, it's a regression. > >> although a crossover cable is available if that becomes an option. >> >> Can someone in the group advise me on how to debug this issue? I was >> hoping to get a back trace for you guys... > Have you considered logging in over the network? > > What exactly do you want to learn? kgdb may not be the best way of > learning it. > > The log in your previous message wasn't very intelligible. You had too > many debug options turned on, which is almost as bad as not having > enough. > > 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
