Call libusb_get_next_timeout() to get minimum timeout for g_poll().

We should have been doing this all along, but we get away with it
on Linux where libusb can do everything with fds, and we get away
with it for many drivers that have a short timeout on their events.

On Windows though, handling this correctly is essential.

Fixes bug #343.

diff --git a/src/session.c b/src/session.c
index 276c5d17a997dc8cc93b2321b71c4259373043ab..0780a27ab3d2476e80df9e5af32ad184eb3bd9b4 100644 (file)
--- a/src/session.c
+++ b/src/session.c
@@ -379,10 +379,27 @@ SR_API int sr_session_trigger_set(struct sr_session *session, struct sr_trigger
 static int sr_session_iteration(struct sr_session *session, gboolean block)
 {
        unsigned int i;
-       int ret;
+       int ret, timeout;
+#ifdef HAVE_LIBUSB_1_0
+       int usb_timeout;
+       struct timeval tv;
+#endif
+
+       timeout = block ? 0 : session->source_timeout;
+
+#ifdef HAVE_LIBUSB_1_0
+       ret = libusb_get_next_timeout(session->ctx->libusb_ctx, &tv);
+       if (ret < 0) {
+               sr_err("Error getting libusb timeout: %s",
+                       libusb_error_name(ret));
+               return SR_ERR;
+       } else if (ret == 1) {
+               usb_timeout = tv.tv_sec * 1000 + tv.tv_usec / 1000;
+               timeout = MIN(timeout, usb_timeout);
+       }
+#endif
 
-       ret = g_poll(session->pollfds, session->num_sources,
-                       block ? session->source_timeout : 0);
+       ret = g_poll(session->pollfds, session->num_sources, timeout);
        for (i = 0; i < session->num_sources; i++) {
                if (session->pollfds[i].revents > 0 || (ret == 0
                        && session->source_timeout == session->sources[i].timeout)) {