From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: To: 9fans@9fans.net From: Richard Miller <9fans@hamnavoe.com> Date: Thu, 14 Feb 2013 10:23:07 +0000 In-Reply-To: <4442f092af66fdb18489c9e964583fb8@brasstown.quanstro.net> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [9fans] usb serial bug Topicbox-Message-UUID: 176733a4-ead8-11e9-9d60-3106f5b1d025 > 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.