On Wed, 30 Oct 2002, Greg KH wrote:

>On Wed, Oct 30, 2002 at 04:08:41PM -0500, Dan Streetman wrote:
>> 
>> On Wed, 30 Oct 2002, Greg KH wrote:
>> 
>> >On Wed, Oct 30, 2002 at 01:53:29PM -0500, Dan Streetman wrote:
>> >> 
>> >> This patch sets up the URB interval correctly when using interrupts via 
>> >> usbfs.  This is finally possible since the automagic resubmission is gone.
>> >
>> >Hm, I don't understand, what does this patch do that couldn't be done
>> >before?  Oh, we were forced to do "one shot" interrupt urbs before,
>> >right?  How does this patch change the way userspace programs that
>> >were used to the old way work?
>> 
>> There is no change to userspace programs.  Before the interval was set to 
>> 0 (one-shot), this changes usbfs to use the endpoint's requested interval 
>> (bInterval).
>
>But wouldn't any program that expected a one shot interrupt, be
>supprised with this change?  Or am I just missing something really basic
>here?

well, 'one-shot' was just setting the interval to 0, which did 2 
things: told the HCD to put the URB on the fastest possible polling 
interval, and don't automatically resubmit it.  Since there's no automatic
resubmission anymore, the 'one-shot' does nothing more than poll too fast.  

The other way of handling the interval is add a usbdevfs_urb->interval 
field, but that would require userspace driver changes, and isn't needed - 
a driver shouldn't be polling an endpoint at a different interval than the 
endpoint requests.


-- 
Dan Streetman
[EMAIL PROTECTED]
---------------------
186,272 miles per second:
It isn't just a good idea, it's the law!



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