Am Dienstag, 24. April 2007 12:06 schrieb Wael Adel:
> On 4/24/07, Oliver Neukum <[EMAIL PROTECTED]> wrote:
> > Am Dienstag, 24. April 2007 11:46 schrieb Wael Adel:
> > > retval = usb_submit_urb(urb, GFP_KERNEL);
> > > if (retval) {
> > > err("%s - failed submitting write urb, error %d",
> > __FUNCTION__, retval);
> > > goto error;
> > > }
> > >
> > > if (buf != NULL)
> > > {
> > > if (copy_to_user(user_buffer, buf , readsize))
> > > {
> > > retval = -EFAULT;
> > > goto error;
> > > }
> > > }
> >
> > You are copying the the buffer to user space without waiting for the
> > URB to be executed. That cannot work.
>
> so how can i wait for the urb to be executed then copying the data to
> the user space?
> is there a flag that i should loop on it or what?
- init an instance of "struct completion"
- submit the URB, passing a pointer to the struct completion
- use wait_for_completion()
- in the completion handler call complete()
HTH
Oliver
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