On Fri, Jan 03, 2014 at 01:21:18PM -0800, walt wrote: > I'm so sorry Sarah, that was another mistake. The mistake is so stupid I'm not > going to publish it here :( > > Once I finally ran the kernel with debugging actually compiled in, dmesg contains > xhci debugging messages. Wow :) > > It's a big file so I zipped and attached it, which I hope is acceptable in lkml. Yep, that's fine. Sticking it in pastebin (or up on your server) is also fine, if it gets really big. > BTW, this dmesg is from a kernel with sg_tablesize = 31, which as I said before > doesn't fix the problem. The cp stopped around 7GB just as before. > > Sorry for the noise... No worries! :) With the dmesg, I can finally see what happened: [ 188.703059] xhci_hcd 0000:03:00.0: Cancel URB ffff8800b7d2e0c0, dev 1, ep 0x2, starting at offset 0xbb7b9000 [ 188.703072] xhci_hcd 0000:03:00.0: // Ding dong! [ 193.711022] xhci_hcd 0000:03:00.0: xHCI host not responding to stop endpoint command. [ 193.711029] xhci_hcd 0000:03:00.0: Assuming host is dying, halting host. [ 193.711046] xhci_hcd 0000:03:00.0: // Halt the HC [ 193.711060] xhci_hcd 0000:03:00.0: Killing URBs for slot ID 1, ep index 0 [ 193.711066] xhci_hcd 0000:03:00.0: Killing URBs for slot ID 1, ep index 2 [ 193.711078] xhci_hcd 0000:03:00.0: Killing URBs for slot ID 1, ep index 3 [ 193.711096] xhci_hcd 0000:03:00.0: Calling usb_hc_died() [ 193.711103] xhci_hcd 0000:03:00.0: HC died; cleaning up [ 193.711116] xhci_hcd 0000:03:00.0: xHCI host controller is dead. It seems that the xHCI driver tried to stop the endpoint ring in order to cancel a SCSI transfer, and the driver never got a response for that. The offset is rather suspicious (0xbb7b9000), and it probably means the driver attempted to cancel a transfer that had been moved to the beginning of the ring segment, with no-op TRBs before the link TRB. I suspect David's patch triggers a bug in the command cancellation code. There's also the unlikely possibility that the no-op TRBs did indeed cause the host to hang. Either way, I'll have to look into it. I'll let you know when I have some diagnostic patches ready. Sarah Sharp -- 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
