drm/vc4: Export fence through syncobj

Allow specifying a syncobj on render job submission where we store the
fence for the job. This gives userland flexible access to the fence.

v2: Use 0 as invalid syncobj to drop flag (Eric)
    Don't reintroduce the padding (Eric)

Signed-off-by: Stefan Schake <stschake@gmail.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/1524607427-12876-3-git-send-email-stschake@gmail.com

diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index e305ccd..a4c4be3 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -656,7 +656,8 @@ retry:
  */
 static int
 vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec,
-                struct ww_acquire_ctx *acquire_ctx)
+                struct ww_acquire_ctx *acquire_ctx,
+                struct drm_syncobj *out_sync)
 {
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_exec_info *renderjob;
@@ -679,6 +680,9 @@ vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec,
        fence->seqno = exec->seqno;
        exec->fence = &fence->base;
 
+       if (out_sync)
+               drm_syncobj_replace_fence(out_sync, exec->fence);
+
        vc4_update_bo_seqnos(exec, seqno);
 
        vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
@@ -1114,6 +1118,7 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_file *vc4file = file_priv->driver_priv;
        struct drm_vc4_submit_cl *args = data;
+       struct drm_syncobj *out_sync = NULL;
        struct vc4_exec_info *exec;
        struct ww_acquire_ctx acquire_ctx;
        struct dma_fence *in_fence;
@@ -1201,12 +1206,33 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
        if (ret)
                goto fail;
 
+       if (args->out_sync) {
+               out_sync = drm_syncobj_find(file_priv, args->out_sync);
+               if (!out_sync) {
+                       ret = -EINVAL;
+                       goto fail;
+               }
+
+               /* We replace the fence in out_sync in vc4_queue_submit since
+                * the render job could execute immediately after that call.
+                * If it finishes before our ioctl processing resumes the
+                * render job fence could already have been freed.
+                */
+       }
+
        /* Clear this out of the struct we'll be putting in the queue,
         * since it's part of our stack.
         */
        exec->args = NULL;
 
-       ret = vc4_queue_submit(dev, exec, &acquire_ctx);
+       ret = vc4_queue_submit(dev, exec, &acquire_ctx, out_sync);
+
+       /* The syncobj isn't part of the exec data and we need to free our
+        * reference even if job submission failed.
+        */
+       if (out_sync)
+               drm_syncobj_put(out_sync);
+
        if (ret)
                goto fail;
 

diff --git a/include/uapi/drm/vc4_drm.h b/include/uapi/drm/vc4_drm.h
index d97065b..2be4fe3 100644 (file)
--- a/include/uapi/drm/vc4_drm.h
+++ b/include/uapi/drm/vc4_drm.h
@@ -187,6 +187,12 @@ struct drm_vc4_submit_cl {
         * will not start until the syncobj is signaled. 0 means ignore.
         */
        __u32 in_sync;
+
+       /* Syncobj handle to export fence to. If set, the fence in the syncobj
+        * will be replaced with a fence that signals upon completion of this
+        * render job. 0 means ignore.
+        */
+       __u32 out_sync;
 };
 
 /**