[PATCH] drm: Add crtc_queue_syncobj and crtc_get_syncobj ioctls

From: Keith Packard
Date: Fri Apr 06 2018 - 20:02:27 EST


crtc_queue_syncobj creates a new syncobj that will get signaled at a
specified vblank sequence count.

crtc_get_syncobj returns the time and vblank sequence count when the
syncobj was signaled.

The pair of these allows use of syncobjs instead of events for
monitoring vblank activity.

Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
---
drivers/gpu/drm/drm_file.c | 5 +
drivers/gpu/drm/drm_internal.h | 4 +
drivers/gpu/drm/drm_ioctl.c | 2 +
drivers/gpu/drm/drm_syncobj.c | 13 ++-
drivers/gpu/drm/drm_vblank.c | 212 +++++++++++++++++++++++++++++++++++++----
include/drm/drm_file.h | 11 ++-
include/drm/drm_syncobj.h | 13 +++
include/uapi/drm/drm.h | 17 ++++
8 files changed, 253 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index b3c6e997ccdb..c1ada3fe70b0 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -37,6 +37,7 @@

#include <drm/drm_file.h>
#include <drm/drmP.h>
+#include <drm/drm_syncobj.h>

#include "drm_legacy.h"
#include "drm_internal.h"
@@ -711,6 +712,10 @@ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
dma_fence_put(e->fence);
}

+ if (e->syncobj) {
+ drm_syncobj_put(e->syncobj);
+ }
+
if (!e->file_priv) {
kfree(e);
return;
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index c9d5a6cd4d41..71b9435b5b37 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -75,6 +75,10 @@ int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data,

int drm_crtc_queue_sequence_ioctl(struct drm_device *dev, void *data,
struct drm_file *filp);
+int drm_crtc_queue_syncobj_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *filp);
+int drm_crtc_get_syncobj_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *filp);

/* drm_auth.c */
int drm_getmagic(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 4aafe4802099..309611fb5d0d 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -665,6 +665,8 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
DRM_UNLOCKED|DRM_RENDER_ALLOW),
DRM_IOCTL_DEF(DRM_IOCTL_CRTC_GET_SEQUENCE, drm_crtc_get_sequence_ioctl, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_CRTC_QUEUE_SEQUENCE, drm_crtc_queue_sequence_ioctl, DRM_UNLOCKED),
+ DRM_IOCTL_DEF(DRM_IOCTL_CRTC_QUEUE_SYNCOBJ, drm_crtc_queue_syncobj_ioctl, DRM_UNLOCKED),
+ DRM_IOCTL_DEF(DRM_IOCTL_CRTC_GET_SYNCOBJ, drm_crtc_get_syncobj_ioctl, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_LEASE, drm_mode_create_lease_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_LIST_LESSEES, drm_mode_list_lessees_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE, drm_mode_get_lease_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index cb4d09c70fd4..e197b007079d 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -208,7 +208,7 @@ static const struct dma_fence_ops drm_syncobj_null_fence_ops = {
.release = NULL,
};

-static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
+int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj, bool signal)
{
struct drm_syncobj_null_fence *fence;
fence = kzalloc(sizeof(*fence), GFP_KERNEL);
@@ -218,7 +218,8 @@ static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
spin_lock_init(&fence->lock);
dma_fence_init(&fence->base, &drm_syncobj_null_fence_ops,
&fence->lock, 0, 0);
- dma_fence_signal(&fence->base);
+ if (signal)
+ dma_fence_signal(&fence->base);

drm_syncobj_replace_fence(syncobj, &fence->base);

@@ -226,6 +227,7 @@ static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)

return 0;
}
+EXPORT_SYMBOL(drm_syncobj_assign_null_handle);

int drm_syncobj_find_fence(struct drm_file *file_private,
u32 handle,
@@ -283,7 +285,7 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
spin_lock_init(&syncobj->lock);

if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
- ret = drm_syncobj_assign_null_handle(syncobj);
+ ret = drm_syncobj_assign_null_handle(syncobj, true);
if (ret < 0) {
drm_syncobj_put(syncobj);
return ret;
@@ -341,7 +343,7 @@ static int drm_syncobj_create_as_handle(struct drm_file *file_private,
return ret;
}

-static int drm_syncobj_destroy(struct drm_file *file_private,
+int drm_syncobj_destroy(struct drm_file *file_private,
u32 handle)
{
struct drm_syncobj *syncobj;
@@ -356,6 +358,7 @@ static int drm_syncobj_destroy(struct drm_file *file_private,
drm_syncobj_put(syncobj);
return 0;
}
+EXPORT_SYMBOL(drm_syncobj_destroy);

static int drm_syncobj_file_release(struct inode *inode, struct file *file)
{
@@ -973,7 +976,7 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data,
return ret;

for (i = 0; i < args->count_handles; i++) {
- ret = drm_syncobj_assign_null_handle(syncobjs[i]);
+ ret = drm_syncobj_assign_null_handle(syncobjs[i], true);
if (ret < 0)
break;
}
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 32d9bcf5be7f..422a5b1d3b92 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -26,6 +26,7 @@

#include <drm/drm_vblank.h>
#include <drm/drmP.h>
+#include <drm/drm_syncobj.h>
#include <linux/export.h>

#include "drm_trace.h"
@@ -806,25 +807,33 @@ static void send_vblank_event(struct drm_device *dev,
u64 seq, ktime_t now)
{
struct timespec64 tv;
+ struct drm_syncobj *syncobj = e->base.syncobj;

- switch (e->event.base.type) {
- case DRM_EVENT_VBLANK:
- case DRM_EVENT_FLIP_COMPLETE:
- tv = ktime_to_timespec64(now);
- e->event.vbl.sequence = seq;
- /*
- * e->event is a user space structure, with hardcoded unsigned
- * 32-bit seconds/microseconds. This is safe as we always use
- * monotonic timestamps since linux-4.15
- */
- e->event.vbl.tv_sec = tv.tv_sec;
- e->event.vbl.tv_usec = tv.tv_nsec / 1000;
- break;
- case DRM_EVENT_CRTC_SEQUENCE:
+ if (syncobj) {
if (seq)
- e->event.seq.sequence = seq;
- e->event.seq.time_ns = ktime_to_ns(now);
- break;
+ syncobj->sequence = seq;
+ syncobj->time = now;
+ }
+ if (e->base.event) {
+ switch (e->event.base.type) {
+ case DRM_EVENT_VBLANK:
+ case DRM_EVENT_FLIP_COMPLETE:
+ tv = ktime_to_timespec64(now);
+ e->event.vbl.sequence = seq;
+ /*
+ * e->event is a user space structure, with hardcoded unsigned
+ * 32-bit seconds/microseconds. This is safe as we always use
+ * monotonic timestamps since linux-4.15
+ */
+ e->event.vbl.tv_sec = tv.tv_sec;
+ e->event.vbl.tv_usec = tv.tv_nsec / 1000;
+ break;
+ case DRM_EVENT_CRTC_SEQUENCE:
+ if (seq)
+ e->event.seq.sequence = seq;
+ e->event.seq.time_ns = ktime_to_ns(now);
+ break;
+ }
}
trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe, seq);
drm_send_event_locked(dev, &e->base);
@@ -1837,3 +1846,172 @@ int drm_crtc_queue_sequence_ioctl(struct drm_device *dev, void *data,
kfree(e);
return ret;
}
+
+/*
+ * Create a syncobj that is signaled when the specified vblank
+ * occurs.
+ */
+int drm_crtc_queue_syncobj_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_crtc *crtc;
+ struct drm_vblank_crtc *vblank;
+ int pipe;
+ struct drm_crtc_queue_syncobj *queue_syncobj = data;
+ ktime_t now;
+ struct drm_pending_vblank_event *e;
+ struct drm_syncobj *syncobj;
+ u32 syncobj_handle;
+ u32 flags;
+ u64 seq;
+ u64 req_seq;
+ int ret;
+ unsigned long spin_flags;
+
+ if (!drm_core_check_feature(dev, DRIVER_MODESET))
+ return -EINVAL;
+
+ if (!dev->irq_enabled)
+ return -EINVAL;
+
+ crtc = drm_crtc_find(dev, file_priv, queue_syncobj->crtc_id);
+ if (!crtc)
+ return -ENOENT;
+
+ flags = queue_syncobj->flags;
+ /* Check valid flag bits */
+ if (flags & ~(DRM_CRTC_SEQUENCE_RELATIVE|
+ DRM_CRTC_SEQUENCE_NEXT_ON_MISS))
+ return -EINVAL;
+
+ pipe = drm_crtc_index(crtc);
+
+ vblank = &dev->vblank[pipe];
+
+ /*
+ * Allocate all of the necessary objects --
+ * a drm_pending_vblank, drm_syncobj, drm_syncobj handle and dma_fence
+ */
+
+ /* drm_pending_vblank_event */
+ e = kzalloc(sizeof(*e), GFP_KERNEL);
+ if (e == NULL)
+ return -ENOMEM;
+
+ /* syncobj */
+ ret = drm_syncobj_create(&syncobj, 0, NULL);
+ if (ret) {
+ DRM_DEBUG("crtc %d failed to allocate syncobj, %d\n", pipe, ret);
+ goto err_free_event;
+ }
+
+ /*
+ * This allocates the dma_fence object for the syncobj and
+ * leaves it unsignaled.
+ */
+ ret = drm_syncobj_assign_null_handle(syncobj, false);
+ if (ret) {
+ DRM_DEBUG("crtc %d failed to allocate syncobj fence, %d\n", pipe, ret);
+ goto err_free_event;
+ }
+
+ /* and finally the syncobj handle to return to user space */
+ ret = drm_syncobj_get_handle(file_priv, syncobj, &syncobj_handle);
+ if (ret) {
+ DRM_DEBUG("crtc %d failed to allocate syncobj handle, %d\n", pipe, ret);
+ goto err_free_syncobj;
+ }
+
+ ret = drm_crtc_vblank_get(crtc);
+ if (ret) {
+ DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
+ goto err_free_syncobj_handle;
+ }
+
+ seq = drm_vblank_count_and_time(dev, pipe, &now);
+ req_seq = queue_syncobj->sequence;
+
+ if (flags & DRM_CRTC_SEQUENCE_RELATIVE)
+ req_seq += seq;
+
+ if ((flags & DRM_CRTC_SEQUENCE_NEXT_ON_MISS) && vblank_passed(seq, req_seq))
+ req_seq = seq + 1;
+
+ e->pipe = pipe;
+ spin_lock_irqsave(&dev->event_lock, spin_flags);
+
+ /*
+ * drm_crtc_vblank_off() might have been called after we called
+ * drm_crtc_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
+ * vblank disable, so no need for further locking. The reference from
+ * drm_crtc_vblank_get() protects against vblank disable from another source.
+ */
+ if (!READ_ONCE(vblank->enabled)) {
+ ret = -EINVAL;
+ goto err_unlock;
+ }
+
+ e->base.syncobj = syncobj;
+ e->base.fence = drm_syncobj_fence_get(syncobj);
+
+ list_add(&e->base.pending_link, &file_priv->pending_event_list);
+ e->base.file_priv = file_priv;
+
+ e->sequence = req_seq;
+
+ if (vblank_passed(seq, req_seq)) {
+ drm_crtc_vblank_put(crtc);
+ send_vblank_event(dev, e, seq, now);
+ queue_syncobj->sequence = seq;
+ } else {
+ /* drm_handle_vblank_events will call drm_vblank_put */
+ list_add_tail(&e->base.link, &dev->vblank_event_list);
+ queue_syncobj->sequence = req_seq;
+ }
+
+ spin_unlock_irqrestore(&dev->event_lock, spin_flags);
+
+ /* Pass the syncobj handle back to user space */
+ queue_syncobj->handle = syncobj_handle;
+
+ return 0;
+
+err_unlock:
+ spin_unlock_irqrestore(&dev->event_lock, spin_flags);
+ drm_crtc_vblank_put(crtc);
+err_free_syncobj_handle:
+ drm_syncobj_destroy(file_priv, syncobj_handle);
+err_free_syncobj:
+ drm_syncobj_put(syncobj);
+err_free_event:
+ kfree(e);
+ return ret;
+}
+
+int drm_crtc_get_syncobj_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_crtc_get_syncobj *args = data;
+ struct drm_syncobj *syncobj;
+ struct dma_fence *fence;
+
+ if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+ return -ENODEV;
+
+ syncobj = drm_syncobj_find(file_priv, args->handle);
+ if (!syncobj)
+ return -ENOENT;
+
+ /* If there's no fence, it can't have been signaled */
+ fence = syncobj->fence;
+ if (fence == NULL)
+ return -EBUSY;
+
+ if (!dma_fence_is_signaled(fence))
+ return -EBUSY;
+
+ args->sequence = syncobj->sequence;
+ args->sequence_ns = syncobj->time;
+
+ return 0;
+}
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 0e0c868451a5..16de395a2be9 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -106,8 +106,8 @@ struct drm_pending_event {
*
* Pointer to the actual event that should be sent to userspace to be
* read using drm_read(). Can be optional, since nowadays events are
- * also used to signal kernel internal threads with @completion or DMA
- * transactions using @fence.
+ * also used to signal kernel internal threads with @completion, DMA
+ * transactions using @fence or sync objects using @syncobj.
*/
struct drm_event *event;

@@ -119,6 +119,13 @@ struct drm_pending_event {
*/
struct dma_fence *fence;

+ /**
+ * @syncobj:
+ *
+ * Optional Sync Object to signal when the event occurs.
+ */
+ struct drm_syncobj *syncobj;
+
/**
* @file_priv:
*
diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
index 43e2f382d2f0..924f8b880d0c 100644
--- a/include/drm/drm_syncobj.h
+++ b/include/drm/drm_syncobj.h
@@ -65,6 +65,16 @@ struct drm_syncobj {
* a file backing for this syncobj.
*/
struct file *file;
+ /**
+ * @sequence:
+ * crtc sequence number when a vblank syncobj was signaled
+ */
+ uint64_t sequence;
+ /**
+ * @time:
+ * time that a vblank syncobj was signaled
+ */
+ ktime_t time;
};

typedef void (*drm_syncobj_func_t)(struct drm_syncobj *syncobj,
@@ -132,6 +142,7 @@ void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
struct drm_syncobj_cb *cb);
void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
struct dma_fence *fence);
+int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj, bool signal);
int drm_syncobj_find_fence(struct drm_file *file_private,
u32 handle,
struct dma_fence **fence);
@@ -140,6 +151,8 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
struct dma_fence *fence);
int drm_syncobj_get_handle(struct drm_file *file_private,
struct drm_syncobj *syncobj, u32 *handle);
+int drm_syncobj_destroy(struct drm_file *file_private,
+ u32 handle);
int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd);

#endif
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 6fdff5945c8a..7a996f73e972 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -759,6 +759,21 @@ struct drm_crtc_queue_sequence {
__u64 user_data; /* user data passed to event */
};

+struct drm_crtc_queue_syncobj {
+ __u32 crtc_id;
+ __u32 flags;
+ __u64 sequence;
+ __u32 handle; /* return syncobj handle */
+ __u32 pad;
+};
+
+struct drm_crtc_get_syncobj {
+ __u32 handle; /* signaled syncobj */
+ __u32 pad;
+ __u64 sequence; /* return: sequence when syncobj was signaled */
+ __u64 sequence_ns; /* return: time when syncobj was signaled */
+};
+
#if defined(__cplusplus)
}
#endif
@@ -843,6 +858,8 @@ extern "C" {

#define DRM_IOCTL_CRTC_GET_SEQUENCE DRM_IOWR(0x3b, struct drm_crtc_get_sequence)
#define DRM_IOCTL_CRTC_QUEUE_SEQUENCE DRM_IOWR(0x3c, struct drm_crtc_queue_sequence)
+#define DRM_IOCTL_CRTC_QUEUE_SYNCOBJ DRM_IOWR(0x3d, struct drm_crtc_queue_syncobj)
+#define DRM_IOCTL_CRTC_GET_SYNCOBJ DRM_IOWR(0x3e, struct drm_crtc_get_syncobj)

#define DRM_IOCTL_UPDATE_DRAW DRM_IOW(0x3f, struct drm_update_draw)

--
2.16.2