drm: Don't race connector registration

I was under the misconception that the sysfs dev stuff can be fully
set up, and then registered all in one step with device_add. That's
true for properties and property groups, but not for parents and child
devices. Those must be fully registered before you can register a
child.

Add a bit of tracking to make sure that asynchronous mst connector
hotplugging gets this right. For consistency we rely upon the implicit
barriers of the connector->mutex, which is taken anyway, to ensure
that at least either the connector or device registration call will
work out.

Mildly tested since I can't reliably reproduce this on my mst box
here.

Reported-by: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1484237756-2720-1-git-send-email-daniel.vetter@ffwll.ch

path: root/tools/build/feature/test-timerfd.c

/*
 * test for timerfd functions used by perf-kvm-stat-live
 */
#include <sys/timerfd.h>

int main(void)
{
	struct itimerspec new_value;

	int fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
	if (fd < 0)
		return 1;

	if (timerfd_settime(fd, 0, &new_value, NULL) != 0)
		return 1;

	return 0;
}