osmo_libusb: Use libusb_get_pollfds() to get initial file descriptors

It seems it is insufficient to register file-descriptor call-backs
with libusb_set_pollfd_notifiers(), but we also need to call
libusb_get_pollfds() once to get the initial set of file descriptors
which may have been created already during libusb_init().

As we don't have a libusb context before libusb_init() returns,
we cannot call libusb_set_pollfd_notifiers() early enough to be
active already during libusb_init().

Change-Id: Icf81014d689ffa738719af68120fa2dedbeec689
changes/38/27038/1
Harald Welte 10 months ago
parent b12dbf76c2
commit a366a89597
  1. 13
      src/usb/osmo_libusb.c

@ -735,6 +735,8 @@ int osmo_libusb_get_ep_addrs(libusb_device_handle *devh, unsigned int if_num,
int osmo_libusb_init(libusb_context **pluctx)
{
libusb_context *luctx = NULL;
const struct libusb_pollfd **pfds;
int rc;
rc = libusb_init(pluctx);
@ -750,6 +752,17 @@ int osmo_libusb_init(libusb_context **pluctx)
libusb_set_pollfd_notifiers(luctx, osmo_usb_added_cb, osmo_usb_removed_cb, luctx);
/* get the initial file descriptors which were created even before during libusb_init() */
pfds = libusb_get_pollfds(luctx);
if (pfds) {
const struct libusb_pollfd **pfds2 = pfds;
const struct libusb_pollfd *pfd;
/* synthesize 'add' call-backs. not sure why libusb doesn't do that by itself? */
for (pfd = *pfds2; pfd; pfd = *++pfds2)
osmo_usb_added_cb(pfd->fd, pfd->events, luctx);
libusb_free_pollfds(pfds);
}
return 0;
}

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