Attachment 117011 Details for Bug 91273 – simple test application to reproduce this bug

simple test application to reproduce this bug

main.c (text/plain), 3.07 KB, created by Boram on 2015-07-09 02:37:28 UTC

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Creator: Boram

Created: 2015-07-09 02:37:28 UTC

Size: 3.07 KB

patch

obsolete

>#include <stdio.h>
>#include <errno.h>
>#include <stdlib.h>
>#include <unistd.h>
>#include <pthread.h>
>#include <poll.h>
>#include <sys/syscall.h>
>#include <wayland-client.h>
>
>#define exit_if_fail(c) { \
>	if (!(c)) { \
>		fprintf (stderr, "%s(%d) '%s' failed.\n", __FUNCTION__, __LINE__, #c); \
>		exit (-1); \
>	} \
>}
>
>static void
>sync_callback(void *data, struct wl_callback *callback, uint32_t serial)
>{
>	wl_callback_destroy (callback);
>}
>
>static const struct wl_callback_listener sync_listener = {
>	sync_callback
>};
>
>void*
>thread_sub (void *data)
>{
>	struct wl_display *display = (struct wl_display*)data;
>	struct wl_event_queue *queue;
>	struct pollfd fds;
>	int ret;
>
>	/* make sure that display is created */
>	while (!display)
>		usleep (10000);
>
>	fds.events = POLLIN;
>	fds.fd = wl_display_get_fd(display);
>	fds.revents = 0;
>
>	/* This queue is fake to test sub-thread. It will do nothing */
>	queue = wl_display_create_queue  (display);
>	exit_if_fail (queue != NULL);
>
>	/* sub-thread */
>	while (1) {
>		while (wl_display_prepare_read_queue (display, queue) != 0)
>			wl_display_dispatch_queue_pending (display, queue);
>		wl_display_flush (display);
>
>		fprintf (stderr, "*** tid(%ld) sub-poll starts\n", syscall(SYS_gettid));
>		ret = poll(&fds, 1, -1);
>		fprintf (stderr, "*** tid(%ld) sub-poll returns %d\n", syscall(SYS_gettid), ret);
>
>		if (ret < 0) {
>			int normal = (errno == EBUSY);
>			wl_display_cancel_read (display);
>			exit_if_fail (normal);
>			continue;
>		} else {
>			/* sub-thread only reads events from display fd */
>			wl_display_read_events (display);
>		}
>	}
>}
>
>static void
>thread_start (struct wl_display *display)
>{
>	pthread_t thread;
>
>	if(pthread_create (&thread, NULL, thread_sub, display) < 0) {
>		fprintf (stdout, "failed: staring thread\n");
>		exit (-1);
>	}
>
>	pthread_detach (thread);
>}
>
>int main(int argc, char *argv[])
>{
>	struct wl_display *display;
>	struct pollfd fds;
>	int ret;
>
>	/* create a display object */
>	display = wl_display_connect (NULL);
>	exit_if_fail (display != NULL);
>
>	/* start sub-thread with the same display object */
>	thread_start (display);
>
>	fds.events = POLLIN;
>	fds.fd = wl_display_get_fd (display);
>	fds.revents = 0;
>
>	/* main-thread */
>	while (1) {
>		struct wl_callback *callback = wl_display_sync (display);
>		exit_if_fail (callback != NULL);
>
>		wl_callback_add_listener(callback, &sync_listener, NULL);
>
>		/* "flush -> dispatch_pending -> poll -> dispatch" this is exactly what
>		 * weston-client and toolkits do to handle reqeusts and events in client
>		 * side. We might can use prepare_read, read_events, and dispatch_pending.
>		 * But it creates problem where mesa uses wl_display_dispatch_queue.
>		 * A thread would block.
>		 */
>		wl_display_flush (display);
>		wl_display_dispatch_pending (display);
>
>		fprintf (stdout, "+++ tid(%ld) main-poll starts\n", syscall(SYS_gettid));
>		ret = poll (&fds, 1, -1);
>		fprintf (stdout, "+++ tid(%ld) main-poll returns %d\n", syscall(SYS_gettid), ret);
>
>		/* main-thread reads and dispatches events. Between main-thread and
>		 * sub-thread, there is competition while reading events from display fd.
>		 */
>		wl_display_dispatch (display);
>	}
>
>	return 0;
>}

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