Date: Tue, 24 May 2005 21:22:52 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: freebsd-usb@freebsd.org, Dirk Gouders <gouders@et.bocholt.fh-ge.de> Subject: Re: poll(2)ing or select(2)ing /dev/usb0 Message-ID: <200505242122.53801.hselasky@c2i.net> In-Reply-To: <200505241053.j4OArR2c000390@musashi.et.bocholt.fh-gelsenkirchen.de> References: <200505241053.j4OArR2c000390@musashi.et.bocholt.fh-gelsenkirchen.de>
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On Tuesday 24 May 2005 12:53, Dirk Gouders wrote: > Hello, > > in the section USB CONTROLLER INTERFACE the manual page usb(4) says > that one can use poll(2) on /dev/usbN to get noticed when USB devices > are connected or disconnected. > > Now, I wrote two small programs to play with poll(2) and select(2) > on /dev/usb0 and see what happens if I connect/disconnect a USB > device, but nothing happens. As the manual page does not say > what events to poll(2) for, I just turned on all bits in the events > mask and the programs work fine on the event interface /dev/usb. > You cannot read data from /dev/usbN, only ioctls are possible on those devices. See "/sys/dev/usb/usb.c" (usbpoll), if you got the source code installed. --HPS
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