Question about pipes and ugen

M. Warner Losh imp at bsdimp.com
Wed Dec 1 19:45:29 PST 2004


In message: <41AE5B3C.8010003 at elischer.org>
            Julian Elischer <julian at elischer.org> writes:
: >Right now, when the usb stack opens a pipe, it resets the pipe using
: >the ClearFeature(Stall) message.  This appears to work great for the
: >vast majority of usb devices that use things like ugen.  However,
: >there are some that do not like this at all.  Fidora Core 1 Linux, for
: >example, never seems to send these reset messages.  Consequently,
: >there are some devices that work well on Linux, but fail utterly on
: >FreeBSD.
: >
: 
: On the other hand linux's usblib sends a ClearFeature(halt) as well, 
: which we don't even have
: in our version yet..
: 
: I'm slowly working on this..

Actually, linux's stack does no such thing in Fidora Core 1.  I've
verified this with a usb sniffer.

: >>From my reading of the standard, it appears that FreeBSD is doing
: >standards conforming things.  Can anybody confirm this?  Even if it is
: >standards conforming, is there a desire for FreeBSD to not do this?
: >
: 
: I believe that this would have to be a "quirk" and enterred into the 
: "quirk" database so that
: such devices don't try do that..  (The quirks database is something we 
: did in SCSI
: and has been duplicated in USB ,where badly behaved devices are 
: identified and
: special behaviour can be requested for them.)

I'm not sure that the pipe open commands have access to the requisite
information...  or if things would even work since the toggle would be
messed up if we don't send this command...

Warner


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