Re: [9fans] usb serial bug

[erik quanstrom <quanstro@quanstro.net>]

On Thu Feb 14 05:24:27 EST 2013, 9fans@hamnavoe.com wrote:
> > 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.
>
>

in that case, shouldn't these three blocks be reverted?

- erik

/n/dump/2012/1201/sys/src/cmd/usb/serial/serial.c:648,654 - /n/dump/2013/0212/sys/src/cmd/usb/serial/serial.c:647,657
  		fprint(2, "serial: openep %d: %r\n", epin);
  		return -1;
  	}
- 	p->epout = openep(ser->dev, epout);
+ 	if(epout == epin){
+ 		incref(p->epin);
+ 		p->epout = p->epin;
+ 	}else
+ 		p->epout = openep(ser->dev, epout);
  	if(p->epout == nil){
  		fprint(2, "serial: openep %d: %r\n", epout);
  		closedev(p->epin);
/n/dump/2012/1201/sys/src/cmd/usb/serial/serial.c:674,681 - /n/dump/2013/0212/sys/src/cmd/usb/serial/serial.c:677,688

  	if(ser->seteps!= nil)
  		ser->seteps(p);
- 	opendevdata(p->epin, OREAD);
- 	opendevdata(p->epout, OWRITE);
+ 	if(p->epin == p->epout)
+ 		opendevdata(p->epin, ORDWR);
+ 	else{
+ 		opendevdata(p->epin, OREAD);
+ 		opendevdata(p->epout, OWRITE);
+ 	}
  	if(p->epin->dfd < 0 ||p->epout->dfd < 0 ||
  	    (ser->hasepintr && p->epintr->dfd < 0)){
  		fprint(2, "serial: open i/o ep data: %r\n");
/n/dump/2012/1201/sys/src/cmd/usb/serial/serial.c:709,717 - /n/dump/2013/0212/sys/src/cmd/usb/serial/serial.c:716,724
  		    ep->dir == Ein && epintr == -1)
  			epintr = ep->id;
  		if(ep->type == Ebulk){
- 			if(ep->dir == Ein && epin == -1)
+ 			if((ep->dir == Ein || ep->dir == Eboth) && epin == -1)
  				epin = ep->id;
- 			if(ep->dir == Eout && epout == -1)
+ 			if((ep->dir == Ein || ep->dir == Eboth) && epout == -1)
  				epout = ep->id;
  		}
  	}