From: Richard Miller <9fans@hamnavoe.com>
To: 9fans@9fans.net
Subject: Re: [9fans] usb serial bug
Date: Thu, 14 Feb 2013 10:23:07 +0000 [thread overview]
Message-ID: <b9c4bbdbf64d4c863276a47dd9b14de8@hamnavoe.com> (raw)
In-Reply-To: <4442f092af66fdb18489c9e964583fb8@brasstown.quanstro.net>
> this is a WORKAROUND. a proper fix would be something
> like allowing ORDWR in usbopen if that is indeed the problem.
No, endpoints are unidirectional by design; in the usb spec there are
no read/write endpoints. The confusing thing in the spec is that two
different endpoints can have the same endpoint number - they are
distinguished by direction. So what looks like a read/write endpoint
number 1 is really two separate endpoints, input ep 1 and output ep 1.
The current Plan 9 usb architecture perpetuates the confusion by
referring to them both with one name epN.1, but you still have to open
them both independently.
next prev parent reply other threads:[~2013-02-14 10:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-14 3:46 erik quanstrom
2013-02-14 10:23 ` Richard Miller [this message]
2013-02-14 14:33 ` erik quanstrom
2013-02-14 15:21 ` Jeff Sickel
2013-02-14 19:24 ` Richard Miller
2013-02-14 19:54 ` Gorka Guardiola
2013-02-14 20:16 ` Gorka Guardiola
2013-02-14 20:44 ` Richard Miller
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