Am 08.08.19 um 11:04 schrieb Lionel Landwerlin:
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)
Signed-off-by: Lionel Landwerlin lionel.g.landwerlin@intel.com Cc: Christian Koenig Christian.Koenig@amd.com Cc: Jason Ekstrand jason@jlekstrand.net Cc: David(ChunMing) Zhou David1.Zhou@amd.com
drivers/gpu/drm/drm_internal.h | 2 ++ drivers/gpu/drm/drm_ioctl.c | 3 ++ drivers/gpu/drm/drm_syncobj.c | 63 +++++++++++++++++++++++++++++++--- include/drm/drm_syncobj.h | 9 +++++ include/uapi/drm/drm.h | 5 ++- 5 files changed, 77 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h index 51a2055c8f18..de5267711a7c 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_sideband_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..7fd99533f78f 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_SIDEBAND, drm_syncobj_sideband_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 b927e482e554..66f4f91baa6d 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -1150,8 +1150,10 @@ 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);
syncobjs[i]->sideband_payload = 0;}
drm_syncobj_array_free(syncobjs, args->count_handles);
@@ -1205,7 +1207,7 @@ drm_syncobj_timeline_signal_ioctl(struct drm_device *dev, void *data, if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE)) return -EOPNOTSUPP;
- if (args->pad != 0)
if (args->flags != 0) return -EINVAL;
if (args->count_handles == 0)
@@ -1276,7 +1278,7 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data, if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE)) return -EOPNOTSUPP;
- if (args->pad != 0)
if (args->flags != 0) return -EINVAL;
if (args->count_handles == 0)
@@ -1312,15 +1314,68 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data, point = dma_fence_is_signaled(last_signaled) ? last_signaled->seqno : to_dma_fence_chain(last_signaled)->prev_seqno;
dma_fence_put(last_signaled);
dma_fence_put(last_signaled);goto error;break;- }
+error:
- drm_syncobj_array_free(syncobjs, args->count_handles);
- return ret;
+}
Those changes above to drm_syncobj_query now look completely unrelated to me.
+int drm_syncobj_sideband_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_private)+{
- struct drm_syncobj_timeline_array *args = data;
- struct drm_syncobj **syncobjs;
- uint64_t __user *points = u64_to_user_ptr(args->points);
- uint32_t i;
- int ret;
- if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
return -EOPNOTSUPP;- if (args->flags != DRM_SYNCOBJ_TIMELINE_ARRAY_GET_SIDEBAND_PAYLOAD &&
args->flags != DRM_SYNCOBJ_TIMELINE_ARRAY_SET_SIDEBAND_PAYLOAD)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++) {
switch (args->flags) {case DRM_SYNCOBJ_TIMELINE_ARRAY_GET_SIDEBAND_PAYLOAD:copy_to_user(&points[i], &syncobjs[i]->sideband_payload, sizeof(uint64_t));ret = ret ? -EFAULT : 0;if (ret)goto error;break;case DRM_SYNCOBJ_TIMELINE_ARRAY_SET_SIDEBAND_PAYLOAD:copy_from_user(&syncobjs[i]->sideband_payload, &points[i], sizeof(uint64_t));ret = ret ? -EFAULT : 0;if (ret)goto error; break;}+error: 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..b587b8e07547 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;
/**
* @sideband_payload: A 64bit side band payload.** We use the sideband 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.*/u64 sideband_payload; };
void drm_syncobj_free(struct kref *kref);
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index 8a5b2f8f8eb9..dfcbaf603aff 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -782,7 +782,9 @@ struct drm_syncobj_timeline_array { __u64 handles; __u64 points; __u32 count_handles;
- __u32 pad;
- __u32 flags;
+#define DRM_SYNCOBJ_TIMELINE_ARRAY_GET_SIDEBAND_PAYLOAD (0) +#define DRM_SYNCOBJ_TIMELINE_ARRAY_SET_SIDEBAND_PAYLOAD (1) };
@@ -946,6 +948,7 @@ 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_SIDEBAND DRM_IOWR(0xCE, struct drm_syncobj_timeline_array)
Maybe better add separate get/set IOCTLs, but just a suggestion.
Regards, Christian.
/**
- Device specific ioctls should only be in their respective headers