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/*
* This is based on an original C++ implementation for compiz that
* carries the following copyright notice:
*
*
* Copyright © 2011 NVIDIA Corporation
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without
* fee, provided that the above copyright notice appear in all copies
* and that both that copyright notice and this permission notice
* appear in supporting documentation, and that the name of NVIDIA
* Corporation not be used in advertising or publicity pertaining to
* distribution of the software without specific, written prior
* permission. NVIDIA Corporation makes no representations about the
* suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* NVIDIA CORPORATION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS, IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*
* Authors: James Jones <jajones@nvidia.com>
*/
#include <string.h>
#include <GL/gl.h>
#include <GL/glx.h>
#include <X11/extensions/sync.h>
#include <cogl/cogl.h>
#include <clutter/clutter.h>
#include <meta/util.h>
#include "meta-sync-ring.h"
/* Theory of operation:
*
* We use a ring of NUM_SYNCS fence objects. On each frame we advance
* to the next fence in the ring. For each fence we do:
*
* 1. fence is XSyncTriggerFence()'d and glWaitSync()'d
* 2. NUM_SYNCS / 2 frames later, fence should be triggered
* 3. fence is XSyncResetFence()'d
* 4. NUM_SYNCS / 2 frames later, fence should be reset
* 5. go back to 1 and re-use fence
*
* glClientWaitSync() and XAlarms are used in steps 2 and 4,
* respectively, to double-check the expectections.
*/
#define NUM_SYNCS 10
#define MAX_SYNC_WAIT_TIME (1 * 1000 * 1000 * 1000) /* one sec */
#define MAX_REBOOT_ATTEMPTS 2
typedef enum
{
META_SYNC_STATE_READY,
META_SYNC_STATE_WAITING,
META_SYNC_STATE_DONE,
META_SYNC_STATE_RESET_PENDING,
} MetaSyncState;
typedef struct
{
Display *xdisplay;
XSyncFence xfence;
GLsync gl_x11_sync;
GLsync gpu_fence;
XSyncCounter xcounter;
XSyncAlarm xalarm;
XSyncValue next_counter_value;
MetaSyncState state;
} MetaSync;
typedef struct
{
Display *xdisplay;
int xsync_event_base;
int xsync_error_base;
GHashTable *alarm_to_sync;
MetaSync *syncs_array[NUM_SYNCS];
guint current_sync_idx;
MetaSync *current_sync;
guint warmup_syncs;
guint reboots;
} MetaSyncRing;
static MetaSyncRing meta_sync_ring = { 0 };
static XSyncValue SYNC_VALUE_ZERO;
static XSyncValue SYNC_VALUE_ONE;
static const char* (*meta_gl_get_string) (GLenum name);
static void (*meta_gl_get_integerv) (GLenum pname,
GLint *params);
static const char* (*meta_gl_get_stringi) (GLenum name,
GLuint index);
static void (*meta_gl_delete_sync) (GLsync sync);
static GLenum (*meta_gl_client_wait_sync) (GLsync sync,
GLbitfield flags,
GLuint64 timeout);
static void (*meta_gl_wait_sync) (GLsync sync,
GLbitfield flags,
GLuint64 timeout);
static GLsync (*meta_gl_import_sync) (GLenum external_sync_type,
GLintptr external_sync,
GLbitfield flags);
static GLsync (*meta_gl_fence_sync) (GLenum condition,
GLbitfield flags);
static MetaSyncRing *
meta_sync_ring_get (void)
{
if (meta_sync_ring.reboots > MAX_REBOOT_ATTEMPTS)
return NULL;
return &meta_sync_ring;
}
static gboolean
load_gl_symbol (const char *name,
void **func)
{
*func = cogl_get_proc_address (name);
if (!*func)
{
meta_verbose ("MetaSyncRing: failed to resolve required GL symbol \"%s\"\n", name);
return FALSE;
}
return TRUE;
}
static gboolean
check_gl_extensions (void)
{
ClutterBackend *backend;
CoglContext *cogl_context;
CoglDisplay *cogl_display;
CoglRenderer *cogl_renderer;
backend = clutter_get_default_backend ();
cogl_context = clutter_backend_get_cogl_context (backend);
cogl_display = cogl_context_get_display (cogl_context);
cogl_renderer = cogl_display_get_renderer (cogl_display);
switch (cogl_renderer_get_driver (cogl_renderer))
{
case COGL_DRIVER_GL3:
{
int num_extensions, i;
gboolean arb_sync = FALSE;
gboolean x11_sync_object = FALSE;
meta_gl_get_integerv (GL_NUM_EXTENSIONS, &num_extensions);
for (i = 0; i < num_extensions; ++i)
{
const char *ext = meta_gl_get_stringi (GL_EXTENSIONS, i);
if (g_strcmp0 ("GL_ARB_sync", ext) == 0)
arb_sync = TRUE;
else if (g_strcmp0 ("GL_EXT_x11_sync_object", ext) == 0)
x11_sync_object = TRUE;
}
return arb_sync && x11_sync_object;
}
case COGL_DRIVER_GL:
{
const char *extensions = meta_gl_get_string (GL_EXTENSIONS);
return (extensions != NULL &&
strstr (extensions, "GL_ARB_sync") != NULL &&
strstr (extensions, "GL_EXT_x11_sync_object") != NULL);
}
default:
break;
}
return FALSE;
}
static gboolean
load_required_symbols (void)
{
static gboolean success = FALSE;
if (success)
return TRUE;
/* We don't link against libGL directly because cogl may want to
* use something else. This assumes that cogl has been initialized
* and dynamically loaded libGL at this point.
*/
if (!load_gl_symbol ("glGetString", (void **) &meta_gl_get_string))
goto out;
if (!load_gl_symbol ("glGetIntegerv", (void **) &meta_gl_get_integerv))
goto out;
if (!load_gl_symbol ("glGetStringi", (void **) &meta_gl_get_stringi))
goto out;
if (!check_gl_extensions ())
{
meta_verbose ("MetaSyncRing: couldn't find required GL extensions\n");
goto out;
}
if (!load_gl_symbol ("glDeleteSync", (void **) &meta_gl_delete_sync))
goto out;
if (!load_gl_symbol ("glClientWaitSync", (void **) &meta_gl_client_wait_sync))
goto out;
if (!load_gl_symbol ("glWaitSync", (void **) &meta_gl_wait_sync))
goto out;
if (!load_gl_symbol ("glImportSyncEXT", (void **) &meta_gl_import_sync))
goto out;
if (!load_gl_symbol ("glFenceSync", (void **) &meta_gl_fence_sync))
goto out;
success = TRUE;
out:
return success;
}
static void
meta_sync_insert (MetaSync *self)
{
g_return_if_fail (self->state == META_SYNC_STATE_READY);
XSyncTriggerFence (self->xdisplay, self->xfence);
XFlush (self->xdisplay);
meta_gl_wait_sync (self->gl_x11_sync, 0, GL_TIMEOUT_IGNORED);
self->gpu_fence = meta_gl_fence_sync (GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
self->state = META_SYNC_STATE_WAITING;
}
static GLenum
meta_sync_check_update_finished (MetaSync *self,
GLuint64 timeout)
{
GLenum status = GL_WAIT_FAILED;
switch (self->state)
{
case META_SYNC_STATE_DONE:
status = GL_ALREADY_SIGNALED;
break;
case META_SYNC_STATE_WAITING:
status = meta_gl_client_wait_sync (self->gpu_fence, 0, timeout);
if (status == GL_ALREADY_SIGNALED || status == GL_CONDITION_SATISFIED)
{
self->state = META_SYNC_STATE_DONE;
meta_gl_delete_sync (self->gpu_fence);
self->gpu_fence = 0;
}
break;
default:
break;
}
g_warn_if_fail (status != GL_WAIT_FAILED);
return status;
}
static void
meta_sync_reset (MetaSync *self)
{
XSyncAlarmAttributes attrs;
int overflow;
g_return_if_fail (self->state == META_SYNC_STATE_DONE);
XSyncResetFence (self->xdisplay, self->xfence);
attrs.trigger.wait_value = self->next_counter_value;
XSyncChangeAlarm (self->xdisplay, self->xalarm, XSyncCAValue, &attrs);
XSyncSetCounter (self->xdisplay, self->xcounter, self->next_counter_value);
XSyncValueAdd (&self->next_counter_value,
self->next_counter_value,
SYNC_VALUE_ONE,
&overflow);
self->state = META_SYNC_STATE_RESET_PENDING;
}
static void
meta_sync_handle_event (MetaSync *self,
XSyncAlarmNotifyEvent *event)
{
g_return_if_fail (event->alarm == self->xalarm);
g_return_if_fail (self->state == META_SYNC_STATE_RESET_PENDING);
self->state = META_SYNC_STATE_READY;
}
static MetaSync *
meta_sync_new (Display *xdisplay)
{
MetaSync *self;
XSyncAlarmAttributes attrs;
self = g_malloc0 (sizeof (MetaSync));
self->xdisplay = xdisplay;
self->xfence = XSyncCreateFence (xdisplay, DefaultRootWindow (xdisplay), FALSE);
self->gl_x11_sync = meta_gl_import_sync (GL_SYNC_X11_FENCE_EXT, self->xfence, 0);
self->gpu_fence = 0;
self->xcounter = XSyncCreateCounter (xdisplay, SYNC_VALUE_ZERO);
attrs.trigger.counter = self->xcounter;
attrs.trigger.value_type = XSyncAbsolute;
attrs.trigger.wait_value = SYNC_VALUE_ONE;
attrs.trigger.test_type = XSyncPositiveTransition;
attrs.events = TRUE;
self->xalarm = XSyncCreateAlarm (xdisplay,
XSyncCACounter |
XSyncCAValueType |
XSyncCAValue |
XSyncCATestType |
XSyncCAEvents,
&attrs);
XSyncIntToValue (&self->next_counter_value, 1);
self->state = META_SYNC_STATE_READY;
return self;
}
static Bool
alarm_event_predicate (Display *dpy,
XEvent *event,
XPointer data)
{
MetaSyncRing *ring = meta_sync_ring_get ();
if (!ring)
return False;
if (event->type == ring->xsync_event_base + XSyncAlarmNotify)
{
if (((MetaSync *) data)->xalarm == ((XSyncAlarmNotifyEvent *) event)->alarm)
return True;
}
return False;
}
static void
meta_sync_free (MetaSync *self)
{
/* When our assumptions don't hold, something has gone wrong but we
* don't know what, so we reboot the ring. While doing that, we
* trigger fences before deleting them to try to get ourselves out
* of a potentially stuck GPU state.
*/
switch (self->state)
{
case META_SYNC_STATE_WAITING:
meta_gl_delete_sync (self->gpu_fence);
break;
case META_SYNC_STATE_DONE:
/* nothing to do */
break;
case META_SYNC_STATE_RESET_PENDING:
{
XEvent event;
XIfEvent (self->xdisplay, &event, alarm_event_predicate, (XPointer) self);
meta_sync_handle_event (self, (XSyncAlarmNotifyEvent *) &event);
}
/* fall through */
case META_SYNC_STATE_READY:
XSyncTriggerFence (self->xdisplay, self->xfence);
XFlush (self->xdisplay);
break;
default:
break;
}
meta_gl_delete_sync (self->gl_x11_sync);
XSyncDestroyFence (self->xdisplay, self->xfence);
XSyncDestroyCounter (self->xdisplay, self->xcounter);
XSyncDestroyAlarm (self->xdisplay, self->xalarm);
g_free (self);
}
gboolean
meta_sync_ring_init (Display *xdisplay)
{
gint major, minor;
guint i;
MetaSyncRing *ring = meta_sync_ring_get ();
if (!ring)
return FALSE;
g_return_val_if_fail (xdisplay != NULL, FALSE);
g_return_val_if_fail (ring->xdisplay == NULL, FALSE);
if (!load_required_symbols ())
return FALSE;
if (!XSyncQueryExtension (xdisplay, &ring->xsync_event_base, &ring->xsync_error_base) ||
!XSyncInitialize (xdisplay, &major, &minor))
return FALSE;
XSyncIntToValue (&SYNC_VALUE_ZERO, 0);
XSyncIntToValue (&SYNC_VALUE_ONE, 1);
ring->xdisplay = xdisplay;
ring->alarm_to_sync = g_hash_table_new (NULL, NULL);
for (i = 0; i < NUM_SYNCS; ++i)
{
MetaSync *sync = meta_sync_new (ring->xdisplay);
ring->syncs_array[i] = sync;
g_hash_table_replace (ring->alarm_to_sync, (gpointer) sync->xalarm, sync);
}
ring->current_sync_idx = 0;
ring->current_sync = ring->syncs_array[0];
ring->warmup_syncs = 0;
return TRUE;
}
void
meta_sync_ring_destroy (void)
{
guint i;
MetaSyncRing *ring = meta_sync_ring_get ();
if (!ring)
return;
g_return_if_fail (ring->xdisplay != NULL);
ring->current_sync_idx = 0;
ring->current_sync = NULL;
ring->warmup_syncs = 0;
for (i = 0; i < NUM_SYNCS; ++i)
meta_sync_free (ring->syncs_array[i]);
g_hash_table_destroy (ring->alarm_to_sync);
ring->xsync_event_base = 0;
ring->xsync_error_base = 0;
ring->xdisplay = NULL;
}
static gboolean
meta_sync_ring_reboot (Display *xdisplay)
{
MetaSyncRing *ring = meta_sync_ring_get ();
if (!ring)
return FALSE;
meta_sync_ring_destroy ();
ring->reboots += 1;
if (!meta_sync_ring_get ())
{
meta_warning ("MetaSyncRing: Too many reboots -- disabling\n");
return FALSE;
}
return meta_sync_ring_init (xdisplay);
}
gboolean
meta_sync_ring_after_frame (void)
{
MetaSyncRing *ring = meta_sync_ring_get ();
if (!ring)
return FALSE;
g_return_val_if_fail (ring->xdisplay != NULL, FALSE);
if (ring->warmup_syncs >= NUM_SYNCS / 2)
{
guint reset_sync_idx = (ring->current_sync_idx + NUM_SYNCS - (NUM_SYNCS / 2)) % NUM_SYNCS;
MetaSync *sync_to_reset = ring->syncs_array[reset_sync_idx];
GLenum status = meta_sync_check_update_finished (sync_to_reset, 0);
if (status == GL_TIMEOUT_EXPIRED)
{
meta_warning ("MetaSyncRing: We should never wait for a sync -- add more syncs?\n");
status = meta_sync_check_update_finished (sync_to_reset, MAX_SYNC_WAIT_TIME);
}
if (status != GL_ALREADY_SIGNALED && status != GL_CONDITION_SATISFIED)
{
meta_warning ("MetaSyncRing: Timed out waiting for sync object.\n");
return meta_sync_ring_reboot (ring->xdisplay);
}
meta_sync_reset (sync_to_reset);
}
else
{
ring->warmup_syncs += 1;
}
ring->current_sync_idx += 1;
ring->current_sync_idx %= NUM_SYNCS;
ring->current_sync = ring->syncs_array[ring->current_sync_idx];
return TRUE;
}
gboolean
meta_sync_ring_insert_wait (void)
{
MetaSyncRing *ring = meta_sync_ring_get ();
if (!ring)
return FALSE;
g_return_val_if_fail (ring->xdisplay != NULL, FALSE);
if (ring->current_sync->state != META_SYNC_STATE_READY)
{
meta_warning ("MetaSyncRing: Sync object is not ready -- were events handled properly?\n");
if (!meta_sync_ring_reboot (ring->xdisplay))
return FALSE;
}
meta_sync_insert (ring->current_sync);
return TRUE;
}
void
meta_sync_ring_handle_event (XEvent *xevent)
{
XSyncAlarmNotifyEvent *event;
MetaSync *sync;
MetaSyncRing *ring = meta_sync_ring_get ();
if (!ring)
return;
g_return_if_fail (ring->xdisplay != NULL);
if (xevent->type != (ring->xsync_event_base + XSyncAlarmNotify))
return;
event = (XSyncAlarmNotifyEvent *) xevent;
sync = g_hash_table_lookup (ring->alarm_to_sync, (gpointer) event->alarm);
if (sync)
meta_sync_handle_event (sync, event);
}