Re: [PATCHv2] usb: gadget: get rid of USB_GADGET_DUALSPEED andUSB_GADGET_SUPERSPEED

[Michal Nazarewicz]

> On Wed, 17 Aug 2011, Michal Nazarewicz wrote:
> > --- a/drivers/usb/gadget/composite.c
> > +++ b/drivers/usb/gadget/composite.c
> > @@ -1559,12 +1559,6 @@ composite_resume(struct usb_gadget *gadget)
> >  /*-------------------------------------------------------------------------*/
> >
> >  static struct usb_gadget_driver composite_driver = {
> > -#ifdef CONFIG_USB_GADGET_SUPERSPEED
> > -	.speed		= USB_SPEED_SUPER,
> > -#else
> > -	.speed		= USB_SPEED_HIGH,
> > -#endif
> > -
> >  	.unbind		= composite_unbind,
> >
> >  	.setup		= composite_setup,
> > @@ -1609,8 +1603,7 @@ int usb_composite_probe(struct  
> > usb_composite_driver *driver,
> >  		driver->iProduct = driver->name;
> >  	composite_driver.function =  (char *) driver->name;
> >  	composite_driver.driver.name = driver->name;
> > -	composite_driver.speed = min((u8)composite_driver.speed,
> > -				     (u8)driver->max_speed);
> > +	composite_driver.speed = driver->max_speed;
> >  	composite = driver;
> >  	composite_gadget_bind = bind;

On Wed, 17 Aug 2011 23:09:37 +0200, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>  
wrote:
> I see what's going on here.  Your original patch was wrong and then my
> correction was wrong as well.
>
> This line has to remain the way it was (although those (u8) typecasts
> don't seem to be necessary).  Above, you have to initialize
> composite_driver.speed to an appropriate value, probably
> USB_SPEED_SUPER.
>
> What you didn't realize in your original patch is that
> usb_composite_probe() gets called more than once.  Each time it is
> called, it has to adjust composite_driver.speed.

That's sneaky of composite.c...  But is it desired behaviour?  I cannot
came up with a situation where that's what we want.  I would imagine that
usb_composite_probe() should assume the same speed for given
usb_composite_driver regardless if some other slower usb_composite_driver
was loaded.

--
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michal "mina86" Nazarewicz    (o o)
ooo +-----<email/xmpp: mnazarewicz@xxxxxxxxxx>-----ooO--(_)--Ooo--
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