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/* Compile with:
*
* gcc -osyncobj-eventfd $(pkg-config libdrm --cflags --libs) syncobj-eventfd.c
*/
#define _GNU_SOURCE
#include <assert.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/eventfd.h>
#include <unistd.h>
#include <xf86drm.h>
#define DRM_IOCTL_SYNCOBJ_EVENTFD DRM_IOWR(0xCE, struct drm_syncobj_eventfd)
struct drm_syncobj_eventfd {
__u32 handle;
__u32 flags;
__u64 point;
__s32 fd;
__u32 pad;
};
int main(void)
{
int drm_fd, ev_fd, ret;
uint32_t handle;
struct drm_syncobj_eventfd arg;
uint64_t ev_fd_value;
drm_fd = open("/dev/dri/renderD128", O_RDWR | O_CLOEXEC);
assert(drm_fd >= 0);
ret = drmSyncobjCreate(drm_fd, 0, &handle);
assert(ret == 0);
ev_fd = eventfd(0, EFD_CLOEXEC);
assert(ev_fd >= 0);
arg = (struct drm_syncobj_eventfd) {
.handle = handle,
.fd = ev_fd,
};
ret = drmIoctl(drm_fd, DRM_IOCTL_SYNCOBJ_EVENTFD, &arg);
assert(ret == 0);
ret = fork();
assert(ret >= 0);
if (ret == 0) {
ret = read(ev_fd, &ev_fd_value, sizeof(ev_fd_value));
assert(ret > 0);
printf("Event FD signalled!\n");
_exit(0);
}
sleep(3);
printf("Signalling drm_syncobj\n");
ret = drmSyncobjSignal(drm_fd, &handle, 1);
assert(ret == 0);
sleep(1);
return 0;
}