On Sun, 21 Mar 2010, Bruno Prémont wrote:
> > > + }
> > > + data->status |= PICOLCD_BUSY;
> > > + data->pending = work;
> > > + for (i = k = 0; i < report->maxfield; i++)
> > > + for (j = 0; j < report->field[i]->report_count; j++) {
> > > + hid_set_field(report->field[i], j, k < size ? raw_data[k] : 0);
> > > + k++;
> > > + }
> > > + usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
> > > + complete_all(&data->ready);
> > > + INIT_COMPLETION(data->ready);
> >
> > Umm, what does this do, exactly?
> >
> It wakes up anyone waiting on the completion and then resets the completion
> as otherwise any future attempt to wait on it would succeed immediately.
>
> The complete_all() instead of just complete() comes from the reset() function.
> I can probably reduce it here.
>
> Will check this combined with your mutex suggestion above.
I am afraid this code is racy as is. You can't be sure that whoever has
been waiting on the completion has been notified already between
complete_all() and INIT_COMPLETION(), can you?
Thanks for the driver!
--
Jiri Kosina
SUSE Labs, Novell Inc.
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