Hi Keith, You've told me in the past that you've run into an issue where you can hang the xHCI driver when one of your TeleMetrum boards refuses to respond to a Set Address command. Can you test the following patchset, and see if it fixes your problem? I've applied the patchset against 3.13 here: https://git.kernel.org/cgit/linux/kernel/git/sarah/xhci.git/log/?h=for-usb-next-command-queue Thanks, Sarah Sharp On Mon, Jan 13, 2014 at 05:05:49PM +0200, Mathias Nyman wrote: > This is an attempt to re-work and solve the issues in xhci command > queue management that Sarah has descibed earlier: > > Right now, the command management in the xHCI driver is rather ad-hock. > Different parts of the driver all submit commands, including interrupt > handling routines, functions called from the USB core (with or without the > bus bandwidth mutex held). > Some times they need to wait for the command to complete, and sometimes > they just issue the command and don't care about the result of the command. > > The places that wait on a command all time the command for five seconds, > and then attempt to cancel the command. > Unfortunately, that means if several commands are issued at once, and one of > them times out, all the commands timeout, even though the host hasn't gotten > a chance to service them yet. > > This is apparent with some devices that take a long time to respond to the > Set Address command during device enumeration (when the device is plugged in). > If a driver for a different device attempts to change alternate interface > settings at the same time (causing a Configure Endpoint command to be issued), > both commands timeout. > > Instead of having each command timeout after five seconds, the driver should > wait indefinitely in an uninterruptible sleep on the command completion. > A global command queue manager should time whatever command is currently > running, and cancel that command after five seconds. > > If the commands were in a list, like TDs currently are, it may be easier to keep > track of where the command ring dequeue pointer is, and avoid racing with events. > We may need to have parts of the driver that issue commands without waiting on > them still put the commands in the command list. > > The Implementation: > ------------------- > > First step is to create a list of the commands submitted to the command queue. > To accomplish this each command is required to be submitted with a properly > filled command structure containing completion, status variable and a pointer to > the command TRB that will be used. > > The first 7 patches are all about creating these command structures and > submitting them when we queue commands. > The command structures are allocated on the fly, the commands that are submitted > in interrupt context are allocated with GFP_ATOMIC. > > Next, the global command queue is introduced. Commands are added to the queue > when trb's are queued, and remove when the commad completes. > Also switch to use the status variable and completion in the command struct. > > A new timer handles command timeout, the timer is kicked every time when a > command finishes and there's a new command waiting in the queue, or when a new > command is submitted to an _empty_ command queue. > Timer is deleted when the the last command on the queue finishes (empty queue) > > The old cancel_cmd_list is removed. > When the timer expires we simply tag the current command as "ABORTED" and start > the ring abortion process. Functions waiting for an aborted command to finish are > called after the command abortion is completed. > > Mathias Nyman (10): > xhci: Use command structures when calling xhci_configure_endpoint > xhci: use a command structure internally in xhci_address_device() > xhci: use command structures for xhci_queue_slot_control() > xhci: use command structures for xhci_queue_stop_endpoint() > xhci: use command structure for xhci_queue_new_dequeue_state() > xhci: use command structures for xhci_queue_reset_ep() > xhci: Use command structured when queuing commands > xhci: Add a global command queue > xhci: Use completion and status in global command queue > xhci: rework command timeout and cancellation, > > drivers/usb/host/xhci-hub.c | 42 ++-- > drivers/usb/host/xhci-mem.c | 22 +- > drivers/usb/host/xhci-ring.c | 532 ++++++++++++++----------------------------- > drivers/usb/host/xhci.c | 264 +++++++++++---------- > drivers/usb/host/xhci.h | 43 ++-- > 5 files changed, 373 insertions(+), 530 deletions(-) > > -- > 1.8.1.2 > -- 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
