The Vulkan timeline semaphores allow
signaling to happen on the point
of the timeline without all of the its dependencies to be
created.
The current 2 implementations (AMD/Intel) of the Vulkan
spec on top of
the Linux kernel are using a thread to wait on the
dependencies of a
given point to materialize and delay actual submission to
the kernel
driver until the wait completes.
If a binary semaphore is submitted for signaling along the
side of a
timeline semaphore waiting for completion that means that
the drm
syncobj associated with that binary semaphore will not
have a DMA
fence associated with it by the time vkQueueSubmit()
returns. This and
the fact that a binary semaphore can be signaled and
unsignaled as
before its DMA fences materialize mean that we cannot just
rely on the
fence within the syncobj but we also need a sideband
payload verifying
that the fence in the syncobj matches the last submission
from the
Vulkan API point of view.
This change adds a sideband payload that is incremented
with signaled
syncobj when vkQueueSubmit() is called. The next
vkQueueSubmit()
waiting on a the syncobj will read the sideband payload
and wait for a
fence chain element with a seqno superior or equal to the
sideband
payload value to be added into the fence chain and use
that fence to
trigger the submission on the kernel driver.
v2: Use a separate ioctl to get/set the sideband value
(Christian)
v3: Use 2 ioctls for get/set (Christian)
v4: Use a single new ioctl
v5: a bunch of blattant mistakes
Store payload atomically (Chris)
v6: Only touch atomic value once (Jason)
v7: Updated atomic value when importing sync file
Signed-off-by: Lionel Landwerlin
<lionel.g.landwerlin@xxxxxxxxx>
Reviewed-by: David Zhou
<David1.Zhou@xxxxxxx> (v6)
Cc: Christian Koenig
<Christian.Koenig@xxxxxxx>
Cc: Jason Ekstrand
<jason@xxxxxxxxxxxxxx>
Cc: David(ChunMing) Zhou
<David1.Zhou@xxxxxxx>
---
drivers/gpu/drm/drm_internal.h | 2 ++
drivers/gpu/drm/drm_ioctl.c | 3 ++
drivers/gpu/drm/drm_syncobj.c | 64
++++++++++++++++++++++++++++++++--
include/drm/drm_syncobj.h | 9 +++++
include/uapi/drm/drm.h | 17 +++++++++
5 files changed, 93 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_internal.h
b/drivers/gpu/drm/drm_internal.h
index 51a2055c8f18..e297dfd85019 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -208,6 +208,8 @@ int
drm_syncobj_timeline_signal_ioctl(struct drm_device *dev,
void *data,
struct drm_file
*file_private);
int drm_syncobj_query_ioctl(struct drm_device *dev, void
*data,
struct drm_file
*file_private);
+int drm_syncobj_binary_ioctl(struct drm_device *dev, void
*data,
+ struct drm_file
*file_private);
/* drm_framebuffer.c */
void drm_framebuffer_print_info(struct drm_printer *p,
unsigned int indent,
diff --git a/drivers/gpu/drm/drm_ioctl.c
b/drivers/gpu/drm/drm_ioctl.c
index f675a3bb2c88..644d0bc800a4 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -703,6 +703,9 @@ static const struct drm_ioctl_desc
drm_ioctls[] = {
DRM_RENDER_ALLOW),
DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_QUERY,
drm_syncobj_query_ioctl,
DRM_RENDER_ALLOW),
+ DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_BINARY,
drm_syncobj_binary_ioctl,
+ DRM_RENDER_ALLOW),
+
DRM_IOCTL_DEF(DRM_IOCTL_CRTC_GET_SEQUENCE,
drm_crtc_get_sequence_ioctl, 0),
DRM_IOCTL_DEF(DRM_IOCTL_CRTC_QUEUE_SEQUENCE,
drm_crtc_queue_sequence_ioctl, 0),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_LEASE,
drm_mode_create_lease_ioctl, DRM_MASTER),
diff --git a/drivers/gpu/drm/drm_syncobj.c
b/drivers/gpu/drm/drm_syncobj.c
index 4b5c7b0ed714..2de8f1380890 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -418,8 +418,10 @@ int drm_syncobj_create(struct
drm_syncobj **out_syncobj, uint32_t flags,
if (flags & DRM_SYNCOBJ_CREATE_SIGNALED)
drm_syncobj_assign_null_handle(syncobj);
- if (fence)
+ if (fence) {
drm_syncobj_replace_fence(syncobj,
fence);
+
atomic64_set(&syncobj->binary_payload,
fence->seqno);
+ }
*out_syncobj = syncobj;
return 0;
@@ -604,6 +606,7 @@ static int
drm_syncobj_import_sync_file_fence(struct drm_file
*file_private,
}
drm_syncobj_replace_fence(syncobj, fence);
+ atomic64_set(&syncobj->binary_payload,
fence->seqno);
dma_fence_put(fence);
drm_syncobj_put(syncobj);
return 0;
@@ -1224,8 +1227,10 @@ drm_syncobj_reset_ioctl(struct
drm_device *dev, void *data,
if (ret < 0)
return ret;
- for (i = 0; i < args->count_handles; i++)
+ for (i = 0; i < args->count_handles; i++) {
drm_syncobj_replace_fence(syncobjs[i],
NULL);
+
atomic64_set(&syncobjs[i]->binary_payload, 0);
+ }
drm_syncobj_array_free(syncobjs,
args->count_handles);
@@ -1395,6 +1400,61 @@ int drm_syncobj_query_ioctl(struct
drm_device *dev, void *data,
if (ret)
break;
}
+
+ drm_syncobj_array_free(syncobjs,
args->count_handles);
+
+ return ret;
+}
+
+int drm_syncobj_binary_ioctl(struct drm_device *dev, void
*data,
+ struct drm_file
*file_private)
+{
+ struct drm_syncobj_binary_array *args = data;
+ struct drm_syncobj **syncobjs;
+ u32 __user *access_flags =
u64_to_user_ptr(args->access_flags);
+ u64 __user *values =
u64_to_user_ptr(args->values);
+ u32 i;
+ int ret;
+
+ if (!drm_core_check_feature(dev,
DRIVER_SYNCOBJ_TIMELINE))
+ return -EOPNOTSUPP;
+
+ if (args->pad != 0)
+ return -EINVAL;
+
+ if (args->count_handles == 0)
+ return -EINVAL;
+
+ ret = drm_syncobj_array_find(file_private,
+
u64_to_user_ptr(args->handles),
+
args->count_handles,
+ &syncobjs);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < args->count_handles; i++) {
+ u32 flags;
+ u64 value;
+
+ if (get_user(flags, &access_flags[i]))
{
+ ret = -EFAULT;
+ break;
+ }
+
+ if (flags &
DRM_SYNCOBJ_BINARY_VALUE_INC)
+ value =
atomic64_inc_return(&syncobjs[i]->binary_payload) -
1;
+ else if (flags &
DRM_SYNCOBJ_BINARY_VALUE_READ)
+ value =
atomic64_read(&syncobjs[i]->binary_payload);
+
+ if (flags &
DRM_SYNCOBJ_BINARY_VALUE_READ) {
+ if (put_user(value,
&values[i])) {
+ ret = -EFAULT;
+ break;
+ }
+ }
+
+ }
+
drm_syncobj_array_free(syncobjs,
args->count_handles);
return ret;
diff --git a/include/drm/drm_syncobj.h
b/include/drm/drm_syncobj.h
index 6cf7243a1dc5..aa76cb3f9107 100644
--- a/include/drm/drm_syncobj.h
+++ b/include/drm/drm_syncobj.h
@@ -61,6 +61,15 @@ struct drm_syncobj {
* @file: A file backing for this syncobj.
*/
struct file *file;
+ /**
+ * @binary_payload: A 64bit payload for binary
syncobjs.
+ *
+ * We use the payload value to wait on binary
syncobj fences to
+ * materialize. It is a reservation mechanism for
the signaler to
+ * express that at some point in the future a dma
fence with the same
+ * seqno will be put into the syncobj.
+ */
+ atomic64_t binary_payload;
};
void drm_syncobj_free(struct kref *kref);
diff --git a/include/uapi/drm/drm.h
b/include/uapi/drm/drm.h
index 8a5b2f8f8eb9..78a0a413b788 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -785,6 +785,22 @@ struct drm_syncobj_timeline_array {
__u32 pad;
};
+struct drm_syncobj_binary_array {
+ /* A pointer to an array of u32 syncobj handles.
*/
+ __u64 handles;
+ /* A pointer to an array of u32 access flags for
each handle. */
+ __u64 access_flags;
+ /* The binary value of a syncobj is read before it
is incremented. */
+#define DRM_SYNCOBJ_BINARY_VALUE_READ (1u << 0)
+#define DRM_SYNCOBJ_BINARY_VALUE_INC (1u << 1)
+ /* A pointer to an array of u64 values written to
by the kernel if the
+ * handle is flagged for reading.
+ */
+ __u64 values;
+ /* The length of the 3 arrays above. */
+ __u32 count_handles;
+ __u32 pad;
+};
/* Query current scanout sequence number */
struct drm_crtc_get_sequence {
@@ -946,6 +962,7 @@ extern "C" {
#define DRM_IOCTL_SYNCOBJ_QUERY DRM_IOWR(0xCB,
struct drm_syncobj_timeline_array)
#define DRM_IOCTL_SYNCOBJ_TRANSFER DRM_IOWR(0xCC,
struct drm_syncobj_transfer)
#define DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL
DRM_IOWR(0xCD, struct drm_syncobj_timeline_array)
+#define DRM_IOCTL_SYNCOBJ_BINARY DRM_IOWR(0xCE,
struct drm_syncobj_binary_array)
/**
* Device specific ioctls should only be in their
respective headers
--
2.23.0
