Hi,
when using dmix as an ALSA output, the output cannot be polled and
ALSA (snd_pcm_poll_descriptors) returns the event mask set to POLLIN
instead. As this event mask is passed to the main loop, the select()
in main_loop_wait() never waits, because the output file descriptor is
never read. So, qemu/kvm ends up busy looping all the time.
The attached patch simply disables the poll mode, when ALSA returns
POLLIN in the event mask for the ALSA playback pcm handle.
--
Jindrich Makovicka
--- alsaaudio.c.orig 2010-10-13 12:55:11.000000000 +0200
+++ alsaaudio.c 2010-10-17 12:18:57.928834276 +0200
@@ -266,8 +266,13 @@
for (i = 0; i < count; ++i) {
if (pfds[i].events & POLLIN) {
- err = qemu_set_fd_handler (pfds[i].fd, alsa_poll_handler,
- NULL, hlp);
+ if (mask & POLLIN) {
+ err = qemu_set_fd_handler (pfds[i].fd, alsa_poll_handler,
+ NULL, hlp);
+ } else {
+ dolog ("Cannot use poll mode for output\n");
+ err = -1;
+ }
}
if (pfds[i].events & POLLOUT) {
if (conf.verbose) {
