On Thu, 26 May 2011, Tanya Brokhman wrote: > > > Right, but at this point there is no way of knowing what function > > drivers > > > will bind to it and what descriptors they will provide. Most of the > > > function drivers allocate their descriptors at bind() that occurs > > after > > > the UDC already registers. > > > > Well, there must be an appropriate spot to do this. > > Unfortunately in the current implementation there isn't. Sure there is. You describe a good possibility later on in your email... > > It looks like you need to add a "max_speed" field to struct > > usb_composite_driver. Each driver will initialize this to the highest > > speed it supports, and it must guarantee that the necessary descriptors > > are available. > > I also thought of that. This can be done... > Just to make sure we're on the same page: > We can add a "max_sup_speed" field to struct usb_composite_driver. Each of > the Gadget drivers will set this field prior to calling > usb_composite_probe(). Then, in usb_composite_probe(), we'll update the > composite_driver.speed as follows: > > composite_driver.speed = min(composite_driver.speed, > driver->max_sup_speed); Just call it max_speed. You can mention in the kerneldoc that it is the maximum speed supported by the driver. > Of course for SS we'll update the composite_driver.speed @ static struct > usb_gadget_driver composite_driver, as we agreed with Felipe. > > How does that sound? Felipe - it seems to me that these should cover your > hesitations about updating the driver speed :) > > Now that I think about it, the above will be true for HS as well. I mean the > current speed of composite_driver is set always to HS but if there is a > function driver that supports only FS then the above will update > composite_driver.speed to FS. That's right. The same solution will work for both cases. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
