gstreamer/gst/gstsystemclock.c
Jonas Holmberg abffdb2ac3 Implement the systemclock with gstpoll
Add a property to select the clock type, currently REALTIME and MONOTONIC when
posix timers are available.

Implement the systemclock with GstPoll instead of GCond. This allows us to
schedule timeouts with nanosecond precission on newer kernels and with ppoll
support. It's also resilient to changes to the systemclock because of NTP or
similar.
2009-02-03 18:04:46 +01:00

767 lines
24 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2004 Wim Taymans <wim@fluendo.com>
*
* gstsystemclock.c: Default clock, uses the system clock
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstsystemclock
* @short_description: Default clock that uses the current system time
* @see_also: #GstClock
*
* The GStreamer core provides a GstSystemClock based on the system time.
* Asynchronous callbacks are scheduled from an internal thread.
*
* Clock implementors are encouraged to subclass this systemclock as it
* implements the async notification.
*
* Subclasses can however override all of the important methods for sync and
* async notifications to implement their own callback methods or blocking
* wait operations.
*
* Last reviewed on 2006-03-08 (0.10.4)
*/
#include "gst_private.h"
#include "gstinfo.h"
#include "gstsystemclock.h"
#include "gstpoll.h"
/* Define this to get some extra debug about jitter from each clock_wait */
#undef WAIT_DEBUGGING
#define GST_TYPE_CLOCK_TYPE (gst_clock_type_get_type())
struct _GstSystemClockPrivate
{
GstClockType clock_type;
GstPoll *timer;
gint async_wakeup_count;
};
#define GST_SYSTEM_CLOCK_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_SYSTEM_CLOCK, \
GstSystemClockPrivate))
enum
{
PROP_0,
PROP_CLOCK_TYPE,
/* FILL ME */
};
/* the one instance of the systemclock */
static GstClock *_the_system_clock = NULL;
static void gst_system_clock_class_init (GstSystemClockClass * klass);
static void gst_system_clock_init (GstSystemClock * clock);
static void gst_system_clock_dispose (GObject * object);
static void gst_system_clock_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_system_clock_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstClockTime gst_system_clock_get_internal_time (GstClock * clock);
static guint64 gst_system_clock_get_resolution (GstClock * clock);
static GstClockReturn gst_system_clock_id_wait_jitter (GstClock * clock,
GstClockEntry * entry, GstClockTimeDiff * jitter);
static GstClockReturn gst_system_clock_id_wait_jitter_unlocked
(GstClock * clock, GstClockEntry * entry, GstClockTimeDiff * jitter,
gboolean restart);
static GstClockReturn gst_system_clock_id_wait_async (GstClock * clock,
GstClockEntry * entry);
static void gst_system_clock_id_unschedule (GstClock * clock,
GstClockEntry * entry);
static void gst_system_clock_async_thread (GstClock * clock);
static gboolean gst_system_clock_start_async (GstSystemClock * clock);
static GStaticMutex _gst_sysclock_mutex = G_STATIC_MUTEX_INIT;
static GstClockClass *parent_class = NULL;
/* static guint gst_system_clock_signals[LAST_SIGNAL] = { 0 }; */
GType
gst_system_clock_get_type (void)
{
static GType clock_type = 0;
if (G_UNLIKELY (clock_type == 0)) {
static const GTypeInfo clock_info = {
sizeof (GstSystemClockClass),
NULL,
NULL,
(GClassInitFunc) gst_system_clock_class_init,
NULL,
NULL,
sizeof (GstSystemClock),
0,
(GInstanceInitFunc) gst_system_clock_init,
NULL
};
clock_type = g_type_register_static (GST_TYPE_CLOCK, "GstSystemClock",
&clock_info, 0);
}
return clock_type;
}
static GType
gst_clock_type_get_type (void)
{
static GType clock_type_type = 0;
static const GEnumValue clock_types[] = {
{GST_CLOCK_TYPE_REALTIME, "GST_CLOCK_TYPE_REALTIME", "realtime"},
{GST_CLOCK_TYPE_MONOTONIC, "GST_CLOCK_TYPE_MONOTONIC", "monotonic"},
{0, NULL, NULL},
};
if (G_UNLIKELY (!clock_type_type)) {
clock_type_type = g_enum_register_static ("GstClockType", clock_types);
}
return clock_type_type;
}
static void
gst_system_clock_class_init (GstSystemClockClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
GstClockClass *gstclock_class;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
gstclock_class = (GstClockClass *) klass;
parent_class = g_type_class_peek_parent (klass);
g_type_class_add_private (klass, sizeof (GstSystemClockPrivate));
gobject_class->dispose = gst_system_clock_dispose;
gobject_class->set_property = gst_system_clock_set_property;
gobject_class->get_property = gst_system_clock_get_property;
g_object_class_install_property (gobject_class, PROP_CLOCK_TYPE,
g_param_spec_enum ("clock-type", "Clock type",
"The type of underlying clock implementation used",
GST_TYPE_CLOCK_TYPE, GST_CLOCK_TYPE_REALTIME, G_PARAM_READWRITE));
gstclock_class->get_internal_time = gst_system_clock_get_internal_time;
gstclock_class->get_resolution = gst_system_clock_get_resolution;
gstclock_class->wait_jitter = gst_system_clock_id_wait_jitter;
gstclock_class->wait_async = gst_system_clock_id_wait_async;
gstclock_class->unschedule = gst_system_clock_id_unschedule;
}
static void
gst_system_clock_init (GstSystemClock * clock)
{
GST_OBJECT_FLAG_SET (clock,
GST_CLOCK_FLAG_CAN_DO_SINGLE_SYNC |
GST_CLOCK_FLAG_CAN_DO_SINGLE_ASYNC |
GST_CLOCK_FLAG_CAN_DO_PERIODIC_SYNC |
GST_CLOCK_FLAG_CAN_DO_PERIODIC_ASYNC);
clock->priv = GST_SYSTEM_CLOCK_GET_PRIVATE (clock);
clock->priv->clock_type = GST_CLOCK_TYPE_REALTIME;
clock->priv->timer = gst_poll_new_timer ();
#if 0
/* Uncomment this to start the async clock thread straight away */
GST_OBJECT_LOCK (clock);
gst_system_clock_start_async (clock);
GST_OBJECT_UNLOCK (clock);
#endif
}
static void
gst_system_clock_dispose (GObject * object)
{
GstClock *clock = (GstClock *) object;
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GList *entries;
/* else we have to stop the thread */
GST_OBJECT_LOCK (clock);
sysclock->stopping = TRUE;
/* unschedule all entries */
for (entries = clock->entries; entries; entries = g_list_next (entries)) {
GstClockEntry *entry = (GstClockEntry *) entries->data;
GST_CAT_DEBUG (GST_CAT_CLOCK, "unscheduling entry %p", entry);
entry->status = GST_CLOCK_UNSCHEDULED;
}
g_list_free (clock->entries);
clock->entries = NULL;
GST_CLOCK_BROADCAST (clock);
GST_OBJECT_UNLOCK (clock);
if (sysclock->thread)
g_thread_join (sysclock->thread);
sysclock->thread = NULL;
GST_CAT_DEBUG (GST_CAT_CLOCK, "joined thread");
gst_poll_free (sysclock->priv->timer);
G_OBJECT_CLASS (parent_class)->dispose (object);
if (_the_system_clock == clock) {
_the_system_clock = NULL;
GST_CAT_DEBUG (GST_CAT_CLOCK, "disposed system clock");
}
}
static void
gst_system_clock_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK (object);
switch (prop_id) {
case PROP_CLOCK_TYPE:
sysclock->priv->clock_type = g_value_get_enum (value);
GST_CAT_DEBUG (GST_CAT_CLOCK, "clock-type set to %d",
sysclock->priv->clock_type);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_system_clock_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK (object);
switch (prop_id) {
case PROP_CLOCK_TYPE:
g_value_set_enum (value, sysclock->priv->clock_type);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/**
* gst_system_clock_obtain:
*
* Get a handle to the default system clock. The refcount of the
* clock will be increased so you need to unref the clock after
* usage.
*
* Returns: the default clock.
*
* MT safe.
*/
GstClock *
gst_system_clock_obtain (void)
{
GstClock *clock;
g_static_mutex_lock (&_gst_sysclock_mutex);
clock = _the_system_clock;
if (clock == NULL) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "creating new static system clock");
clock = g_object_new (GST_TYPE_SYSTEM_CLOCK,
"name", "GstSystemClock", NULL);
/* we created the global clock; take ownership so
* we can hand out instances later */
gst_object_ref (clock);
gst_object_sink (GST_OBJECT (clock));
_the_system_clock = clock;
g_static_mutex_unlock (&_gst_sysclock_mutex);
} else {
g_static_mutex_unlock (&_gst_sysclock_mutex);
GST_CAT_DEBUG (GST_CAT_CLOCK, "returning static system clock");
}
/* we ref it since we are a clock factory. */
gst_object_ref (clock);
return clock;
}
static void
gst_system_clock_clear_async_wakeups_unlocked (GstSystemClock * sysclock)
{
while (sysclock->priv->async_wakeup_count > 0) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "reading control");
while (!gst_poll_read_control (sysclock->priv->timer)) {
g_warning ("gstsystemclock: read control failed, trying again\n");
}
sysclock->priv->async_wakeup_count--;
}
GST_CLOCK_BROADCAST (sysclock);
}
static void
gst_system_clock_wakeup_async_unlocked (GstSystemClock * sysclock)
{
GST_CAT_DEBUG (GST_CAT_CLOCK, "writing control");
while (!gst_poll_write_control (sysclock->priv->timer)) {
g_warning ("gstsystemclock: write control failed, trying again\n");
}
sysclock->priv->async_wakeup_count++;
}
/* this thread reads the sorted clock entries from the queue.
*
* It waits on each of them and fires the callback when the timeout occurs.
*
* When an entry in the queue was canceled before we wait for it, it is
* simply skipped.
*
* When waiting for an entry, it can become canceled, in that case we don't
* call the callback but move to the next item in the queue.
*
* MT safe.
*/
static void
gst_system_clock_async_thread (GstClock * clock)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "enter system clock thread");
GST_OBJECT_LOCK (clock);
/* signal spinup */
GST_CLOCK_BROADCAST (clock);
/* now enter our (almost) infinite loop */
while (!sysclock->stopping) {
GstClockEntry *entry;
GstClockTime requested;
GstClockReturn res;
/* check if something to be done */
while (clock->entries == NULL) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "no clock entries, waiting..");
/* wait for work to do */
GST_CLOCK_WAIT (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "got signal");
/* clock was stopping, exit */
if (sysclock->stopping)
goto exit;
}
/* pick the next entry */
entry = clock->entries->data;
/* if it was unscheduled, just move on to the next entry */
if (entry->status == GST_CLOCK_UNSCHEDULED) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p was unscheduled", entry);
goto next_entry;
}
requested = entry->time;
/* now wait for the entry, we already hold the lock */
res =
gst_system_clock_id_wait_jitter_unlocked (clock, (GstClockID) entry,
NULL, FALSE);
switch (res) {
case GST_CLOCK_UNSCHEDULED:
/* entry was unscheduled, move to the next */
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry %p unscheduled", entry);
goto next_entry;
case GST_CLOCK_OK:
case GST_CLOCK_EARLY:
{
/* entry timed out normally, fire the callback and move to the next
* entry */
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry %p unlocked", entry);
if (entry->func) {
/* unlock before firing the callback */
GST_OBJECT_UNLOCK (clock);
entry->func (clock, entry->time, (GstClockID) entry,
entry->user_data);
GST_OBJECT_LOCK (clock);
}
if (clock->entries->data != entry) {
/* new entries have been added, clear async wakeups */
gst_system_clock_clear_async_wakeups_unlocked (sysclock);
}
if (entry->type == GST_CLOCK_ENTRY_PERIODIC) {
/* adjust time now */
entry->time = requested + entry->interval;
/* and resort the list now */
clock->entries =
g_list_sort (clock->entries, gst_clock_id_compare_func);
/* and restart */
continue;
} else {
goto next_entry;
}
}
case GST_CLOCK_BUSY:
/* somebody unlocked the entry but is was not canceled, This means that
* either a new entry was added in front of the queue or some other entry
* was canceled. Whatever it is, pick the head entry of the list and
* continue waiting. */
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry %p needs restart", entry);
/* clear async wakeups, if any */
gst_system_clock_clear_async_wakeups_unlocked (sysclock);
continue;
default:
GST_CAT_DEBUG (GST_CAT_CLOCK,
"strange result %d waiting for %p, skipping", res, entry);
g_warning ("%s: strange result %d waiting for %p, skipping",
GST_OBJECT_NAME (clock), res, entry);
goto next_entry;
}
next_entry:
/* we remove the current entry and unref it */
clock->entries = g_list_remove (clock->entries, entry);
gst_clock_id_unref ((GstClockID) entry);
}
exit:
/* signal exit */
GST_CLOCK_BROADCAST (clock);
GST_OBJECT_UNLOCK (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "exit system clock thread");
}
#ifdef HAVE_POSIX_TIMERS
static inline clockid_t
clock_type_to_posix_id (GstClockType clock_type)
{
#ifdef HAVE_MONOTONIC_CLOCK
if (clock_type == GST_CLOCK_TYPE_MONOTONIC)
return CLOCK_MONOTONIC;
else
#endif
return CLOCK_REALTIME;
}
#endif
/* MT safe */
static GstClockTime
gst_system_clock_get_internal_time (GstClock * clock)
{
#ifdef HAVE_POSIX_TIMERS
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
if (G_UNLIKELY (clock_gettime (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
return GST_TIMESPEC_TO_TIME (ts);
#else
GTimeVal timeval;
g_get_current_time (&timeval);
return GST_TIMEVAL_TO_TIME (timeval);
#endif
}
static guint64
gst_system_clock_get_resolution (GstClock * clock)
{
#ifdef HAVE_POSIX_TIMERS
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
if (G_UNLIKELY (clock_getres (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
return GST_TIMESPEC_TO_TIME (ts);
#else
return 1 * GST_USECOND;
#endif
}
/* synchronously wait on the given GstClockEntry.
*
* We do this by blocking on the global clock GCond variable with
* the requested time as a timeout. This allows us to unblock the
* entry by signaling the GCond variable.
*
* Note that signaling the global GCond unlocks all waiting entries. So
* we need to check if an unlocked entry has changed when it unlocks.
*
* Entries that arrive too late are simply not waited on and a
* GST_CLOCK_EARLY result is returned.
*
* should be called with LOCK held.
*
* MT safe.
*/
static GstClockReturn
gst_system_clock_id_wait_jitter_unlocked (GstClock * clock,
GstClockEntry * entry, GstClockTimeDiff * jitter, gboolean restart)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GstClockTime entryt, real, now;
GstClockTimeDiff diff;
/* need to call the overridden method because we want to sync against the time
* of the clock, whatever the subclass uses as a clock. */
real = GST_CLOCK_GET_CLASS (clock)->get_internal_time (clock);
now = gst_clock_adjust_unlocked (clock, real);
/* get the time of the entry */
entryt = GST_CLOCK_ENTRY_TIME (entry);
if (jitter) {
*jitter = GST_CLOCK_DIFF (entryt, now);
}
/* the diff of the entry with the clock is the amount of time we have to
* wait */
diff = entryt - now;
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p"
" time %" GST_TIME_FORMAT
" now %" GST_TIME_FORMAT
" real %" GST_TIME_FORMAT
" diff (time-now) %" G_GINT64_FORMAT,
entry,
GST_TIME_ARGS (entryt), GST_TIME_ARGS (now), GST_TIME_ARGS (real), diff);
if (diff > 0) {
#ifdef WAIT_DEBUGGING
GstClockTime final;
#endif
while (entry->status != GST_CLOCK_UNSCHEDULED) {
gint pollret;
/* mark the entry as busy */
entry->status = GST_CLOCK_BUSY;
GST_OBJECT_UNLOCK (clock);
/* now wait on the entry, it either times out or the fd is written. */
pollret = gst_poll_wait (sysclock->priv->timer, diff);
/* another thread can read the fd before we get the lock */
GST_OBJECT_LOCK (clock);
if (entry->status == GST_CLOCK_UNSCHEDULED) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p unlocked", entry);
while (!gst_poll_read_control (sysclock->priv->timer)) {
g_warning ("gstsystemclock: read control failed, trying again\n");
}
GST_CLOCK_BROADCAST (clock);
} else {
if (pollret != 0) {
/* some other id got unlocked */
if (!restart) {
/* this can happen if the entry got unlocked because of an async
* entry was added to the head of the async queue. */
GST_CAT_DEBUG (GST_CAT_CLOCK, "wakeup waiting for entry %p", entry);
break;
}
/* mark ourselves as EARLY, we release the lock and we could be
* unscheduled ourselves but we don't want the unscheduling thread
* to write on the fd */
entry->status = GST_CLOCK_EARLY;
/* before waiting on the cond, check if another thread read the fd
* before we got the lock */
while (gst_poll_wait (sysclock->priv->timer, 0) > 0) {
GST_CLOCK_WAIT (clock);
}
/* we released the lock in the wait, recheck our status */
if (entry->status == GST_CLOCK_UNSCHEDULED) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p got unscheduled", entry);
break;
}
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p needs to be restarted",
entry);
} else {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p unlocked after timeout",
entry);
}
/* reschedule if gst_poll_wait returned early or we have to reschedule after
* an unlock*/
real = GST_CLOCK_GET_CLASS (clock)->get_internal_time (clock);
now = gst_clock_adjust_unlocked (clock, real);
diff = entryt - now;
if (diff <= 0) {
/* timeout, this is fine, we can report success now */
entry->status = GST_CLOCK_OK;
GST_CAT_DEBUG (GST_CAT_CLOCK,
"entry %p finished, diff %" G_GINT64_FORMAT, entry, diff);
#ifdef WAIT_DEBUGGING
final = gst_system_clock_get_internal_time (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "Waited for %" G_GINT64_FORMAT
" got %" G_GINT64_FORMAT " diff %" G_GINT64_FORMAT
" %g target-offset %" G_GINT64_FORMAT " %g", entryt, now,
now - entryt,
(double) (GstClockTimeDiff) (now - entryt) / GST_SECOND,
(final - target),
((double) (GstClockTimeDiff) (final - target)) / GST_SECOND);
#endif
break;
} else {
GST_CAT_DEBUG (GST_CAT_CLOCK,
"entry %p restart, diff %" G_GINT64_FORMAT, entry, diff);
}
}
}
} else if (diff == 0) {
entry->status = GST_CLOCK_OK;
} else {
entry->status = GST_CLOCK_EARLY;
}
return entry->status;
}
static GstClockReturn
gst_system_clock_id_wait_jitter (GstClock * clock, GstClockEntry * entry,
GstClockTimeDiff * jitter)
{
GstClockReturn ret;
GST_OBJECT_LOCK (clock);
ret = gst_system_clock_id_wait_jitter_unlocked (clock, entry, jitter, TRUE);
GST_OBJECT_UNLOCK (clock);
return ret;
}
/* Start the async clock thread. Must be called with the object lock
* held */
static gboolean
gst_system_clock_start_async (GstSystemClock * clock)
{
GError *error = NULL;
if (clock->thread != NULL)
return TRUE; /* Thread already running. Nothing to do */
clock->thread = g_thread_create ((GThreadFunc) gst_system_clock_async_thread,
clock, TRUE, &error);
if (error)
goto no_thread;
/* wait for it to spin up */
GST_CLOCK_WAIT (clock);
return TRUE;
/* ERRORS */
no_thread:
{
g_warning ("could not create async clock thread: %s", error->message);
}
return FALSE;
}
/* Add an entry to the list of pending async waits. The entry is inserted
* in sorted order. If we inserted the entry at the head of the list, we
* need to signal the thread as it might either be waiting on it or waiting
* for a new entry.
*
* MT safe.
*/
static GstClockReturn
gst_system_clock_id_wait_async (GstClock * clock, GstClockEntry * entry)
{
gboolean empty;
GstSystemClock *sysclock;
sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "adding async entry %p", entry);
GST_OBJECT_LOCK (clock);
/* Start the clock async thread if needed */
if (!gst_system_clock_start_async (sysclock))
goto thread_error;
empty = (clock->entries == NULL);
/* need to take a ref */
gst_clock_id_ref ((GstClockID) entry);
/* insert the entry in sorted order */
clock->entries = g_list_insert_sorted (clock->entries, entry,
gst_clock_id_compare_func);
/* only need to send the signal if the entry was added to the
* front, else the thread is just waiting for another entry and
* will get to this entry automatically. */
if (clock->entries->data == entry) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry added to head");
if (empty) {
/* the list was empty before, signal the cond so that the async thread can
* start taking a look at the queue */
GST_CAT_DEBUG (GST_CAT_CLOCK, "sending signal");
GST_CLOCK_BROADCAST (clock);
} else {
/* the async thread was waiting for an entry, unlock the wait so that it
* looks at the new head entry instead */
gst_system_clock_wakeup_async_unlocked (sysclock);
}
}
GST_OBJECT_UNLOCK (clock);
return GST_CLOCK_OK;
thread_error:
/* Could not start the async clock thread */
return GST_CLOCK_ERROR;
}
/* unschedule an entry. This will set the state of the entry to GST_CLOCK_UNSCHEDULED
* and will signal any thread waiting for entries to recheck their entry.
* We cannot really decide if the signal is needed or not because the entry
* could be waited on in async or sync mode.
*
* MT safe.
*/
static void
gst_system_clock_id_unschedule (GstClock * clock, GstClockEntry * entry)
{
GST_CAT_DEBUG (GST_CAT_CLOCK, "unscheduling entry %p", entry);
GST_OBJECT_LOCK (clock);
if (entry->status == GST_CLOCK_BUSY) {
/* the entry was being busy, wake up all entries so that they recheck their
* status. We cannot wake up just one entry because allocating such a
* datastructure for each entry would be too heavey and unlocking an entry
* is usually done when shutting down or some other exceptional case. */
GST_CAT_DEBUG (GST_CAT_CLOCK, "writing control");
while (!gst_poll_write_control (GST_SYSTEM_CLOCK_CAST (clock)->priv->timer)) {
g_warning ("gstsystemclock: write control failed, trying again\n");
}
}
/* when it leaves the poll, it'll detect the unscheduled */
entry->status = GST_CLOCK_UNSCHEDULED;
GST_OBJECT_UNLOCK (clock);
}