From owner-freebsd-usb@FreeBSD.ORG  Tue May 24 10:53:33 2005
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From: Dirk Gouders <gouders@et.bocholt.fh-ge.de>
To: freebsd-usb@freebsd.org
Date: Tue, 24 May 2005 12:53:27 +0200
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Subject: poll(2)ing or select(2)ing /dev/usb0
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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.

I am now wondering, if it is correct what the manual page says about
poll(2)ing /dev/usbN.  If so, what results should be expected, if
several processes are accessing /dev/usb0 (usually usbd(8) is also
running and it also has opened /dev/usb0 on my machine)?

Dirk