FreeBSD 8: libusb async mode + select(2) = nogo?

[Peer Stritzinger]

Hi,

On Fri, Jul 23, 2010 at 7:21 PM, Hans Petter Selasky <hselasky at c2i.net> wrote:

> Should work, but it might be that the second poll, when you try to process the
> events, don't work like expected. After any event on the two fd's you should
> call "libusb_handle_events_locked()" using a "tv = NULL".

Added some debug printing to make watching these easier:

active config: num_interfaces: 1
interface 0: num_altsetting: 1
if_desc 0: n_ep=4 if_nr=0
max packet on 3.2.6 = 512
setup_usb_fds: read 3
setup_usb_fds: read 6
setup_usb_fds: write 6
setup_usb_fds: nfds 6
calling select ...
returned 1                  -> so select returns once (always as it looks)
check_usb_fds: found desc 3 in readfds
calling libusb_handle_events_timeout
transfer_completed: actual_len: 52    -> and also gets a transfer from
the usb (this resubmits the IN transfer)
setup_usb_fds: read 3
setup_usb_fds: read 6
setup_usb_fds: write 6
setup_usb_fds: nfds 6
calling select ...            -> but here it hangs until a signal

The code that did output this still using libusb_handle_events_timeout()

  rv = libusb_submit_transfer(tr);
  assert(rv == 0);

  sp.pollfds = libusb_get_pollfds(ctx);

  while (1)
    {
      timeout_pending = libusb_get_next_timeout(ctx, &timeout);
      setup_usb_fds (&sp);
      printf("calling select ...\n");
      rv = select(sp.nfds, &sp.readfds, &sp.writefds, &sp.exceptfds,
	     (timeout_pending) ? &timeout : NULL);
      printf("returned %d\n", rv);
      assert (rv >= 0 || errno == EINTR);

      if (rv == 0 || (rv > 0 && check_usb_fds (&sp)))
	{
	  printf ("calling libusb_handle_events_timeout\n");
	  libusb_handle_events_timeout(ctx, NULL);
	}
    }

 -- Peer