Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1214480
| From | Mathias Nyman <mathias.nyman@linux.intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 0/5] usb: xhci: Fix breakage on dual-role case |
| Date | 2015-08-27 13:20 +0200 |
| Message-ID | <q23nP-2PN-5@gated-at.bofh.it> (permalink) |
| References | <pYMtc-3yQ-9@gated-at.bofh.it> <pZs94-65q-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 20.08.2015 10:09, Roger Quadros wrote: > Hi Mathias, Hi > > On 18/08/15 13:39, Roger Quadros wrote: >> Hi, >> >> Plugging and unplugging a USB-OTG adapter with a USB device into a >> am437x-gp-evm dual-role port (USB1) causes XHCI to malfunction >> and USB device to be no longer detected after a few iterations. >> >> The triggering case is so >> 1) USB1 in peripheal mode >> 2) plug OTG adapter with USB device >> 3) USB1 switches to host mode >> 4) Detects new USB device >> 5) unplug OTG adapter >> 6) OTG core tries to remove host controller while new device >> is being processed. >> >> At 6 some races are observed in the XHCI driver causing it to >> malfunction. See kernel log at the end of this mail. >> >> This series tries to address some of the issues. >> Althouth it is not 100% fool proof yet and XHCI can still get >> stuck up for a few seconds occasionally, it did recover always >> in a max of 10 seconds and the USB device was enumerated after >> that. >> >> During a dual-role switch, usb_remove_hcd() and usb_add_hcd() >> will be called consecutively for both Shared and Primary >> HCDs. This can happen asynchronously and we have to be prepared >> for it. >> > > Even after this series I do occasionally see a delay of 5 seconds > during adapter detach. (please see kernel log below). > > Is it possible to further optimize so that when xhci_stop is called > we don't depend entirely on timeout timers to stop queued commands? Yes, sounds reasonable. Command timer and ring could probably be stopped, remaining commands aborted and returned. -Mathias -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread
Re: [PATCH 0/5] usb: xhci: Fix breakage on dual-role case Roger Quadros <rogerq@ti.com> - 2015-08-20 09:10 +0200 Re: [PATCH 0/5] usb: xhci: Fix breakage on dual-role case Mathias Nyman <mathias.nyman@linux.intel.com> - 2015-08-27 13:20 +0200
csiph-web