Re: force USB_SPEED_FULL for device

On Fri, 27 Jul 2007, Gabriel Maganis wrote:

> > A more important question is: Why do you want to change
> > usb_device->speed from USB_SPEED_LOW to USB_SPEED_FULL?  Was there
> > something wrong with the USB_SPEED_LOW setting?
> >
> > Alan Stern
> >
> >
> 
> Hello Alan,
>     I would just like to know what response (if at all, garbage, or
> meaningful) it would give me if I send it a packet "at
> USB_SPEED_FULL". Do I also need to change some fields in the
> usb_device structure? I tried changing the ep0.desc.wMaxPacketSize to
> match a device configured at full speed but it didn't work also.

But why?  If you have a low-speed device like a keyboard and you send
it a packet at full-speed, the device won't be able to receive the
packet.  Hence it won't send a reply, at any speed.  There's no need to 
actually do a test; it can't possibly work.

Alan Stern


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