/*
* Copyright 2009 Jerome Glisse.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
*/
/*
* Authors:
* Jerome Glisse <glisse@freedesktop.org>
* Dave Airlie
*/
#include <linux/seq_file.h>
#include <linux/atomic.h>
#include <linux/wait.h>
#include <linux/kref.h>
#include <linux/slab.h>
#include <linux/firmware.h>
#include <drm/drmP.h>
#include "amdgpu.h"
#include "amdgpu_trace.h"
/*
* Fences
* Fences mark an event in the GPUs pipeline and are used
* for GPU/CPU synchronization. When the fence is written,
* it is expected that all buffers associated with that fence
* are no longer in use by the associated ring on the GPU and
* that the the relevant GPU caches have been flushed.
*/
/**
* amdgpu_fence_write - write a fence value
*
* @ring: ring the fence is associated with
* @seq: sequence number to write
*
* Writes a fence value to memory (all asics).
*/
static void amdgpu_fence_write(struct amdgpu_ring *ring, u32 seq)
{
struct amdgpu_fence_driver *drv = &ring->fence_drv;
if (drv->cpu_addr)
*drv->cpu_addr = cpu_to_le32(seq);
}
/**
* amdgpu_fence_read - read a fence value
*
* @ring: ring the fence is associated with
*
* Reads a fence value from memory (all asics).
* Returns the value of the fence read from memory.
*/
static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
{
struct amdgpu_fence_driver *drv = &ring->fence_drv;
u32 seq = 0;
if (drv->cpu_addr)
seq = le32_to_cpu(*drv->cpu_addr);
else
seq = lower_32_bits(atomic64_read(&drv->last_seq));
return seq;
}
/**
* amdgpu_fence_emit - emit a fence on the requested ring
*
* @ring: ring the fence is associated with
* @owner: creator of the fence
* @fence: amdgpu fence object
*
* Emits a fence command on the requested ring (all asics).
* Returns 0 on success, -ENOMEM on failure.
*/
int amdgpu_fence_emit(struct amdgpu_ring *ring, void *owner,
struct amdgpu_fence **fence)
{
struct amdgpu_device *adev = ring->adev;
/* we are protected by the ring emission mutex */
*fence = kmalloc(sizeof(struct amdgpu_fence), GFP_KERNEL);
if ((*fence) == NULL) {
return -ENOMEM;
}
(*fence)->seq = ++ring->fence_drv.sync_seq[ring->idx];
(*fence)->ring = ring;
(*fence)->owner = owner;
fence_init(&(*fence)->base, &amdgpu_fence_ops,
&ring->fence_drv.fence_queue.lock,
adev->fence_context + ring->idx,
(*fence)->seq);
amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
(*fence)->seq,
AMDGPU_FENCE_FLAG_INT);
return 0;
}
/**
* amdgpu_fence_schedule_fallback - schedule fallback check
*
* @ring: pointer to struct amdgpu_ring
*
* Start a timer as fallback to our interrupts.
*/
static void amdgpu_fence_schedule_fallback(struct amdgpu_ring *ring)
{
mod_timer(&ring->fence_drv.fallback_timer,
jiffies + AMDGPU_FENCE_JIFFIES_TIMEOUT);
}
/**
* amdgpu_fence_activity - check for fence activity
*
* @ring: pointer to struct amdgpu_ring
*
* Checks the current fence value and calculates the last
* signalled fence value. Returns true if activity occured
* on the ring, and the fence_queue should be waken up.
*/
static bool amdgpu_fence_activity(struct amdgpu_ring *ring)
{
uint64_t seq, last_seq, last_emitted;
unsigned count_loop = 0;
bool wake = false;
/* Note there is a scenario here for an infinite loop but it's
* very unlikely to happen. For it to happen, the current polling
* process need to be interrupted by another process and another
* process needs to update the last_seq btw the atomic read and
* xchg of the current process.
*
* More over for this to go in infinite loop there need to be
* continuously new fence signaled ie amdgpu_fence_read needs
* to return a different value each time for both the currently
* polling process and the other process that xchg the last_seq
* btw atomic read and xchg of the current process. And the
* value the other process set as last seq must be higher than
* the seq value we just read. Which means that current process
* need to be interrupted after amdgpu_fence_read and before
* atomic xchg.
*
* To be even more safe we count the number of time we loop and
* we bail after 10 loop just accepting the fact that we might
* have temporarly set the last_seq not to the true real last
* seq but to an older one.
*/
last_seq = atomic64_read(&ring->fence_drv.last_seq);
do {
last_emitted = ring->fence_drv.sync_seq[ring->idx];
seq = amdgpu_fence_read(ring);
seq |= last_seq & 0xffffffff00000000LL;
if (seq < last_seq) {
seq &= 0xffffffff;
seq |= last_emitted & 0xffffffff00000000LL;
}
if (seq <= last_seq || seq > last_emitted) {
break;
}
/* If we loop over we don't want to return without
* checking if a fence is signaled as it means that the
* seq we just read is different from the previous on.
*/
wake = true;
last_seq = seq;
if ((count_loop++) > 10) {
/* We looped over too many time leave with the
* fact that we might have set an older fence
* seq then the current real last seq as signaled
* by the hw.
*/
break;
}
} while (atomic64_xchg(&ring->fence_drv.last_seq, seq) > seq);
if (seq < last_emitted)
amdgpu_fence_schedule_fallback(ring);
return wake;
}
/**
* amdgpu_fence_process - process a fence
*
* @adev: amdgpu_device pointer
* @ring: ring index the fence is associated with
*
* Checks the current fence value and wakes the fence queue
* if the sequence number has increased (all asics).
*/
void amdgpu_fence_process(struct amdgpu_ring *ring)
{
if (amdgpu_fence_activity(ring))
wake_up_all(&ring->fence_drv.fence_queue);
}
/**
* amdgpu_fence_fallback - fallback for hardware interrupts
*
* @work: delayed work item
*
* Checks for fence activity.
*/
static void amdgpu_fence_fallback(unsigned long arg)
{
struct amdgpu_ring *ring = (void *)arg;
amdgpu_fence_process(ring);
}
/**
* amdgpu_fence_seq_signaled - check if a fence sequence number has signaled
*
* @ring: ring the fence is associated with
* @seq: sequence number
*
* Check if the last signaled fence sequnce number is >= the requested
* sequence number (all asics).
* Returns true if the fence has signaled (current fence value
* is >= requested value) or false if it has not (current fence
* value is < the requested value. Helper function for
* amdgpu_fence_signaled().
*/
static bool amdgpu_fence_seq_signaled(struct amdgpu_ring *ring, u64 seq)
{
if (atomic64_read(&ring->fence_drv.last_seq) >= seq)
return true;
/* poll new last sequence at least once */
amdgpu_fence_process(ring);
if (atomic64_read(&ring->fence_drv.last_seq) >= seq)
return true;
return false;
}
/*
* amdgpu_ring_wait_seq_timeout - wait for seq of the specific ring to signal
* @ring: ring to wait on for the seq number
* @seq: seq number wait for
*
* return value:
* 0: seq signaled, and gpu not hang
* -EDEADL: GPU hang detected
* -EINVAL: some paramter is not valid
*/
static int amdgpu_fence_ring_wait_seq(struct amdgpu_ring *ring, uint64_t seq)
{
bool signaled = false;
BUG_ON(!ring);
if (seq > ring->fence_drv.sync_seq[ring->idx])
return -EINVAL;
if (atomic64_read(&ring->fence_drv.last_seq) >= seq)
return 0;
amdgpu_fence_schedule_fallback(ring);
wait_event(ring->fence_drv.fence_queue, (
(signaled = amdgpu_fence_seq_signaled(ring, seq))));
if (signaled)
return 0;
else
return -EDEADLK;
}
/**
* amdgpu_fence_wait_next - wait for the next fence to signal
*
* @adev: amdgpu device pointer
* @ring: ring index the fence is associated with
*
* Wait for the next fence on the requested ring to signal (all asics).
* Returns 0 if the next fence has passed, error for all other cases.
* Caller must hold ring lock.
*/
int amdgpu_fence_wait_next(struct amdgpu_ring *ring)
{
uint64_t seq = atomic64_read(&ring->fence_drv.last_seq) + 1ULL;
if (seq >= ring->fence_drv.sync_seq[ring->idx])
return -ENOENT;
return amdgpu_fence_ring_wait_seq(ring, seq);
}
/**
* amdgpu_fence_wait_empty - wait for all fences to signal
*
* @adev: amdgpu device pointer
* @ring: ring index the fence is associated with
*
* Wait for all fences on the requested ring to signal (all asics).
* Returns 0 if the fences have passed, error for all other cases.
* Caller must hold ring lock.
*/
int amdgpu_fence_wait_empty(struct amdgpu_ring *ring)
{
uint64_t seq = ring->fence_drv.sync_seq[ring->idx];
if (!seq)
return 0;
return amdgpu_fence_ring_wait_seq(ring, seq);
}
/**
* amdgpu_fence_count_emitted - get the count of emitted fences
*
* @ring: ring the fence is associated with
*
* Get the number of fences emitted on the requested ring (all asics).
* Returns the number of emitted fences on the ring. Used by the
* dynpm code to ring track activity.
*/
unsigned amdgpu_fence_count_emitted(struct amdgpu_ring *ring)
{
uint64_t emitted;
/* We are not protected by ring lock when reading the last sequence
* but it's ok to report slightly wrong fence count here.
*/
amdgpu_fence_process(ring);
emitted = ring->fence_drv.sync_seq[ring->idx]
- atomic64_read(&ring->fence_drv.last_seq);
/* to avoid 32bits warp around */
if (emitted > 0x10000000)
emitted = 0x10000000;
return (unsigned)emitted;
}
/**
* amdgpu_fence_need_sync - do we need a semaphore
*
* @fence: amdgpu fence object
* @dst_ring: which ring to check against
*
* Check if the fence needs to be synced against another ring
* (all asics). If so, we need to emit a semaphore.
* Returns true if we need to sync with another ring, false if
* not.
*/
bool amdgpu_fence_need_sync(struct amdgpu_fence *fence,
struct amdgpu_ring *dst_ring)
{
struct amdgpu_fence_driver *fdrv;
if (!fence)
return false;
if (fence->ring == dst_ring)
return false;
/* we are protected by the ring mutex */
fdrv = &dst_ring->fence_drv;
if (fence->seq <= fdrv->sync_seq[fence->ring->idx])
return false;
return true;
}
/**
* amdgpu_fence_note_sync - record the sync point
*
* @fence: amdgpu fence object
* @dst_ring: which ring to check against
*
* Note the sequence number at which point the fence will
* be synced with the requested ring (all asics).
*/
void amdgpu_fence_note_sync(struct amdgpu_fence *fence,
struct amdgpu_ring *dst_ring)
{
struct amdgpu_fence_driver *dst, *src;
unsigned i;
if (!fence)
return;
if (fence->ring == dst_ring)
return;
/* we are protected by the ring mutex */
src = &fence->ring->fence_drv;
dst = &dst_ring->fence_drv;
for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
if (i == dst_ring->idx)
continue;
dst->sync_seq[i] = max(dst->sync_seq[i], src->sync_seq[i]);
}
}
/**
* amdgpu_fence_driver_start_ring - make the fence driver
* ready for use on the requested ring.
*
* @ring: ring to start the fence driver on
* @irq_src: interrupt source to use for this ring
* @irq_type: interrupt type to use for this ring
*
* Make the fence driver ready for processing (all asics).
* Not all asics have all rings, so each asic will only
* start the fence driver on the rings it has.
* Returns 0 for success, errors for failure.
*/
int amdgpu_fence_driver_start_ring(struct amdgpu_ring *ring,
struct amdgpu_irq_src *irq_src,
unsigned irq_type)
{
struct amdgpu_device *adev = ring->adev;
uint64_t index;
if (ring != &adev->uvd.ring) {
ring->fence_drv.cpu_addr = &adev->wb.wb[ring->fence_offs];
ring->fence_drv.gpu_addr = adev->wb.gpu_addr + (ring->fence_offs * 4);
} else {
/* put fence directly behind firmware */
index = ALIGN(adev->uvd.fw->size, 8);
ring->fence_drv.cpu_addr = adev->uvd.cpu_addr + index;
ring->fence_drv.gpu_addr = adev->uvd.gpu_addr + index;
}
amdgpu_fence_write(ring, atomic64_read(&ring->fence_drv.last_seq));
amdgpu_irq_get(adev, irq_src, irq_type);
ring->fence_drv.irq_src = irq_src;
ring->fence_drv.irq_type = irq_type;
ring->fence_drv.initialized = true;
dev_info(adev->dev, "fence driver on ring %d use gpu addr 0x%016llx, "
"cpu addr 0x%p\n", ring->idx,
ring->fence_drv.gpu_addr, ring->fence_drv.cpu_addr);
return 0;
}
/**
* amdgpu_fence_driver_init_ring - init the fence driver
* for the requested ring.
*
* @ring: ring to init the fence driver on
*
* Init the fence driver for the requested ring (all asics).
* Helper function for amdgpu_fence_driver_init().
*/
int amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring)
{
int i, r;
ring->fence_drv.cpu_addr = NULL;
ring->fence_drv.gpu_addr = 0;
for (i = 0; i < AMDGPU_MAX_RINGS; ++i)
ring->fence_drv.sync_seq[i] = 0;
atomic64_set(&ring->fence_drv.last_seq, 0);
ring->fence_drv.initialized = false;
setup_timer(&ring->fence_drv.fallback_timer, amdgpu_fence_fallback,
(unsigned long)ring);
init_waitqueue_head(&ring->fence_drv.fence_queue);
if (amdgpu_enable_scheduler) {
long timeout = msecs_to_jiffies(amdgpu_lockup_timeout);
if (timeout == 0) {
/*
* FIXME:
* Delayed workqueue cannot use it directly,
* so the scheduler will not use delayed workqueue if
* MAX_SCHEDULE_TIMEOUT is set.
* Currently keep it simple and silly.
*/
timeout = MAX_SCHEDULE_TIMEOUT;
}
r = amd_sched_init(&ring->sched, &amdgpu_sched_ops,
amdgpu_sched_hw_submission,
timeout, ring->name);
if (r) {
DRM_ERROR("Failed to create scheduler on ring %s.\n",
ring->name);
return r;
}
}
return 0;
}
/**
* amdgpu_fence_driver_init - init the fence driver
* for all possible rings.
*
* @adev: amdgpu device pointer
*
* Init the fence driver for all possible rings (all asics).
* Not all asics have all rings, so each asic will only
* start the fence driver on the rings it has using
* amdgpu_fence_driver_start_ring().
* Returns 0 for success.
*/
int amdgpu_fence_driver_init(struct amdgpu_device *adev)
{
if (amdgpu_debugfs_fence_init(adev))
dev_err(adev->dev, "fence debugfs file creation failed\n");
return 0;
}
/**
* amdgpu_fence_driver_fini - tear down the fence driver
* for all possible rings.
*
* @adev: amdgpu device pointer
*
* Tear down the fence driver for all possible rings (all asics).
*/
void amdgpu_fence_driver_fini(struct amdgpu_device *adev)
{
int i, r;
mutex_lock(&adev->ring_lock);
for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
struct amdgpu_ring *ring = adev->rings[i];
if (!ring || !ring->fence_drv.initialized)
continue;
r = amdgpu_fence_wait_empty(ring);
if (r) {
/* no need to trigger GPU reset as we are unloading */
amdgpu_fence_driver_force_completion(adev);
}
wake_up_all(&ring->fence_drv.fence_queue);
amdgpu_irq_put(adev, ring->fence_drv.irq_src,
ring->fence_drv.irq_type);
amd_sched_fini(&ring->sched);
del_timer_sync(&ring->fence_drv.fallback_timer);
ring->fence_drv.initialized = false;
}
mutex_unlock(&adev->ring_lock);
}
/**
* amdgpu_fence_driver_suspend - suspend the fence driver
* for all possible rings.
*
* @adev: amdgpu device pointer
*
* Suspend the fence driver for all possible rings (all asics).
*/
void amdgpu_fence_driver_suspend(struct amdgpu_device *adev)
{
int i, r;
mutex_lock(&adev->ring_lock);
for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
struct amdgpu_ring *ring = adev->rings[i];
if (!ring || !ring->fence_drv.initialized)
continue;
/* wait for gpu to finish processing current batch */
r = amdgpu_fence_wait_empty(ring);
if (r) {
/* delay GPU reset to resume */
amdgpu_fence_driver_force_completion(adev);
}
/* disable the interrupt */
amdgpu_irq_put(adev, ring->fence_drv.irq_src,
ring->fence_drv.irq_type);
}
mutex_unlock(&adev->ring_lock);
}
/**
* amdgpu_fence_driver_resume - resume the fence driver
* for all possible rings.
*
* @adev: amdgpu device pointer
*
* Resume the fence driver for all possible rings (all asics).
* Not all asics have all rings, so each asic will only
* start the fence driver on the rings it has using
* amdgpu_fence_driver_start_ring().
* Returns 0 for success.
*/
void amdgpu_fence_driver_resume(struct amdgpu_device *adev)
{
int i;
mutex_lock(&adev->ring_lock);
for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
struct amdgpu_ring *ring = adev->rings[i];
if (!ring || !ring->fence_drv.initialized)
continue;
/* enable the interrupt */
amdgpu_irq_get(adev, ring->fence_drv.irq_src,
ring->fence_drv.irq_type);
}
mutex_unlock(&adev->ring_lock);
}
/**
* amdgpu_fence_driver_force_completion - force all fence waiter to complete
*
* @adev: amdgpu device pointer
*
* In case of GPU reset failure make sure no process keep waiting on fence
* that will never complete.
*/
void amdgpu_fence_driver_force_completion(struct amdgpu_device *adev)
{
int i;
for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
struct amdgpu_ring *ring = adev->rings[i];
if (!ring || !ring->fence_drv.initialized)
continue;
amdgpu_fence_write(ring, ring->fence_drv.sync_seq[i]);
}
}
/*
* Common fence implementation
*/
static const char *amdgpu_fence_get_driver_name(struct fence *fence)
{
return "amdgpu";
}
static const char *amdgpu_fence_get_timeline_name(struct fence *f)
{
struct amdgpu_fence *fence = to_amdgpu_fence(f);
return (const char *)fence->ring->name;
}
/**
* amdgpu_fence_is_signaled - test if fence is signaled
*
* @f: fence to test
*
* Test the fence sequence number if it is already signaled. If it isn't
* signaled start fence processing. Returns True if the fence is signaled.
*/
static bool amdgpu_fence_is_signaled(struct fence *f)
{
struct amdgpu_fence *fence = to_amdgpu_fence(f);
struct amdgpu_ring *ring = fence->ring;
if (atomic64_read(&ring->fence_drv.last_seq) >= fence->seq)
return true;
amdgpu_fence_process(ring);
if (atomic64_read(&ring->fence_drv.last_seq) >= fence->seq)
return true;
return false;
}
/**
* amdgpu_fence_check_signaled - callback from fence_queue
*
* this function is called with fence_queue lock held, which is also used
* for the fence locking itself, so unlocked variants are used for
* fence_signal, and remove_wait_queue.
*/
static int amdgpu_fence_check_signaled(wait_queue_t *wait, unsigned mode, int flags, void *key)
{
struct amdgpu_fence *fence;
struct amdgpu_device *adev;
u64 seq;
int ret;
fence = container_of(wait, struct amdgpu_fence, fence_wake);
adev = fence->ring->adev;
/*
* We cannot use amdgpu_fence_process here because we're already
* in the waitqueue, in a call from wake_up_all.
*/
seq = atomic64_read(&fence->ring->fence_drv.last_seq);
if (seq >= fence->seq) {
ret = fence_signal_locked(&fence->base);
if (!ret)
FENCE_TRACE(&fence->base, "signaled from irq context\n");
else
FENCE_TRACE(&fence->base, "was already signaled\n");
__remove_wait_queue(&fence->ring->fence_drv.fence_queue, &fence->fence_wake);
fence_put(&fence->base);
} else
FENCE_TRACE(&fence->base, "pending\n");
return 0;
}
/**
* amdgpu_fence_enable_signaling - enable signalling on fence
* @fence: fence
*
* This function is called with fence_queue lock held, and adds a callback
* to fence_queue that checks if this fence is signaled, and if so it
* signals the fence and removes itself.
*/
static bool amdgpu_fence_enable_signaling(struct fence *f)
{
struct amdgpu_fence *fence = to_amdgpu_fence(f);
struct amdgpu_ring *ring = fence->ring;
if (atomic64_read(&ring->fence_drv.last_seq) >= fence->seq)
return false;
fence->fence_wake.flags = 0;
fence->fence_wake.private = NULL;
fence->fence_wake.func = amdgpu_fence_check_signaled;
__add_wait_queue(&ring->fence_drv.fence_queue, &fence->fence_wake);
fence_get(f);
if (!timer_pending(&ring->fence_drv.fallback_timer))
amdgpu_fence_schedule_fallback(ring);
FENCE_TRACE(&fence->base, "armed on ring %i!\n", ring->idx);
return true;
}
const struct fence_ops amdgpu_fence_ops = {
.get_driver_name = amdgpu_fence_get_driver_name,
.get_timeline_name = amdgpu_fence_get_timeline_name,
.enable_signaling = amdgpu_fence_enable_signaling,
.signaled = amdgpu_fence_is_signaled,
.wait = fence_default_wait,
.release = NULL,
};
/*
* Fence debugfs
*/
#if defined(CONFIG_DEBUG_FS)
static int amdgpu_debugfs_fence_info(struct seq_file *m, void *data)
{
struct drm_info_node *node = (struct drm_info_node *)m->private;
struct drm_device *dev = node->minor->dev;
struct amdgpu_device *adev = dev->dev_private;
int i, j;
for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
struct amdgpu_ring *ring = adev->rings[i];
if (!ring || !ring->fence_drv.initialized)
continue;
amdgpu_fence_process(ring);
seq_printf(m, "--- ring %d (%s) ---\n", i, ring->name);
seq_printf(m, "Last signaled fence 0x%016llx\n",
(unsigned long long)atomic64_read(&ring->fence_drv.last_seq));
seq_printf(m, "Last emitted 0x%016llx\n",
ring->fence_drv.sync_seq[i]);
for (j = 0; j < AMDGPU_MAX_RINGS; ++j) {
struct amdgpu_ring *other = adev->rings[j];
if (i != j && other && other->fence_drv.initialized &&
ring->fence_drv.sync_seq[j])
seq_printf(m, "Last sync to ring %d 0x%016llx\n",
j, ring->fence_drv.sync_seq[j]);
}
}
return 0;
}
static struct drm_info_list amdgpu_debugfs_fence_list[] = {
{"amdgpu_fence_info", &amdgpu_debugfs_fence_info, 0, NULL},
};
#endif
int amdgpu_debugfs_fence_init(struct amdgpu_device *adev)
{
#if defined(CONFIG_DEBUG_FS)
return amdgpu_debugfs_add_files(adev, amdgpu_debugfs_fence_list, 1);
#else
return 0;
#endif
}
