Hi João, Adding Mathias, who's xHCI's maintainer Joao Pinto <Joao.Pinto@xxxxxxxxxxxx> writes: > Hi Felipe, > > I am trying to bring up a DWC USB 3.0 Host with linux (v4.6-rc5) > running in a ARM64 development board. Just to be clear, is this Juno with dwc3 in FPGA or do you have dwc3 in ASIC? > I have implemented the following suggested fix to overcome the DMA > problem I was having: > > https://lkml.org/lkml/2016/3/31/609 > > I received one interrupt but I am getting cyclic crashes like this: if they happen all the time, it probably means your command ring is completely messed up and no command ever completes. Can you share a more complete snippet of logs? > [<ffffff8008086c60>] __switch_to+0xc8/0xd4 > [<ffffff80086386d4>] __schedule+0x18c/0x5c8 > [<ffffff8008638b48>] schedule+0x38/0x98 > [<ffffff800863b67c>] schedule_timeout+0x160/0x1ac > [<ffffff8008639674>] wait_for_common+0xac/0x150 > [<ffffff800863972c>] wait_for_completion+0x14/0x1c > [<ffffff80084898f4>] xhci_alloc_dev+0xf4/0x2a0 > [<ffffff800844ffd0>] usb_alloc_dev+0x68/0x2cc > [<ffffff8008456994>] hub_event+0x784/0x11f4 > [<ffffff80080ce444>] process_one_work+0x130/0x2f4 > [<ffffff80080ce65c>] worker_thread+0x54/0x434 > [<ffffff80080d40fc>] kthread+0xd4/0xe8 > [<ffffff8008085e10>] ret_from_fork+0x10/0x40 > > Any thoughts about what might be happening? pasting xhci_alloc_dev here: > int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev) > { > struct xhci_hcd *xhci = hcd_to_xhci(hcd); > unsigned long flags; > int ret, slot_id; > struct xhci_command *command; > > command = xhci_alloc_command(xhci, false, false, GFP_KERNEL); > if (!command) > return 0; we allocate a command fine > /* xhci->slot_id and xhci->addr_dev are not thread-safe */ > mutex_lock(&xhci->mutex); > spin_lock_irqsave(&xhci->lock, flags); > command->completion = &xhci->addr_dev; > ret = xhci_queue_slot_control(xhci, command, TRB_ENABLE_SLOT, 0); queue it to the command ring > if (ret) { > spin_unlock_irqrestore(&xhci->lock, flags); > mutex_unlock(&xhci->mutex); > xhci_dbg(xhci, "FIXME: allocate a command ring segment\n"); > kfree(command); > return 0; > } > xhci_ring_cmd_db(xhci); > spin_unlock_irqrestore(&xhci->lock, flags); > > wait_for_completion(command->completion); but the command never completes. I wonder if your command doorbell completed before wait_for_completion() was called, or if it didn't complete at all. Can you enable XHCI debugging logs and try again? (Mathias, what was the easy trick to enable all XHCI debugging logs?) -- balbi
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