Date: Mon, 31 May 2021 15:24:47 +0000 From: bugzilla-noreply@freebsd.org To: usb@FreeBSD.org Subject: [Bug 256296] "No Device" error after using asynchronous API of libusb once Message-ID: <bug-256296-19105@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256296 Bug ID: 256296 Summary: "No Device" error after using asynchronous API of libusb once Product: Base System Version: Unspecified Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: usb Assignee: usb@FreeBSD.org Reporter: sergii.dmytruk@3mdeb.com Background information ---------------------- fwupd project is using libgusb, which is a Glib wrapper for libusb. libgusb uses asynchronous API of libusb with events handled in a separate thread. fwupd works with devices by opening them, performing operations and then closing. How the failure occurs ---------------------- fwupd closes a device before all events of the operation have been processed. This means that when libusb10_handle_events_sub() eventually processes related event, the device gets marked as gone (device_is_gone field). On all future calls libusb_submit_transfer() fails with LIBUSB_ERROR_NO_DEVICE because that flag is set. Effectively this means that a device can be used only once in such a way. As I understand libgusb uses the API as intended and it is implementation of libusb which shouldn't prevent repeated use of a device. Maybe it should wait before closing or just reset the flag on opening the device. -- You are receiving this mail because: You are the assignee for the bug.home | help
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