Date: Sat, 9 Mar 2019 16:42:50 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Konstantin Belousov <kostikbel@gmail.com>, "O'Connor, Daniel" <darius@dons.net.au> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: USB stack getting confused Message-ID: <ea6e2690-1ad7-6c06-49e5-c528013f26c0@selasky.org> In-Reply-To: <20190309152613.GM2492@kib.kiev.ua> References: <E0371188-FD0A-47E1-8378-40239F5C6622@dons.net.au> <f3e6e30b-8b62-546b-2b51-e841f2e645bd@selasky.org> <3B29D870-41F9-46AF-B9F3-03106DEC417D@dons.net.au> <20190309152613.GM2492@kib.kiev.ua>
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On 3/9/19 4:26 PM, Konstantin Belousov wrote: > On Sat, Mar 09, 2019 at 08:59:30PM +1030, O'Connor, Daniel wrote: >> >> >>> On 9 Mar 2019, at 19:30, Hans Petter Selasky <hps@selasky.org> wrote: >>> On 3/9/19 12:08 AM, O'Connor, Daniel wrote: >>>> My program normally runs continually doing acquisitions of data for N seconds, doing some checks and restarting. After a while (~30 1 minute acquisitions or ~8 30 minute ones) my program can't 'see' the device (it uses libusb10) any more (it reconnects each acquisition for $REASONS). Also pretty weirdly usbconfig can't see it either(!). >>> >>> What is printed in dmesg? Maybe the device has a problem. >> >> There is nothing in dmesg - no disconnect / reconnect etc. >> >> If I hold the user space process in gdb 'forever' (eg over night) usbconfig doesn't see the device, but the moment I quit the user space process it can be seen again. > > Does it mean that the file descriptor opened for ugen has a chance to > be closed ? The USB stack will wait for all FDs to be closed during detach also via destroy_dev(). > > I suspect that usb subsystem tried to destroy the device but some internal > refcounting prevents it. Proper use of destroy_dev(_cb)(9) avoids > the issue. --HPS
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