[RFC PATCH v1 1/2] drm/syncobj: Add DRM_IOCTL_SYNCOBJ_QUERY_ERROR to query fence error status

[Yicong Hui <yiconghui@gmail.com>]

Add DRM_IOCTL_SYNCOBJ_QUERY_ERROR to allow userspace to query the error
status of a fence held by a timeline/binary syncobj.

Signed-off-by: Yicong Hui <yiconghui@gmail.com>
---
 drivers/gpu/drm/drm_internal.h |  2 ++
 drivers/gpu/drm/drm_ioctl.c    |  2 ++
 drivers/gpu/drm/drm_syncobj.c  | 22 ++++++++++++++++++++++
 include/uapi/drm/drm.h         | 13 +++++++++++++
 4 files changed, 39 insertions(+)

diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index f893b1e3a596..d4d722983544 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -285,6 +285,8 @@ 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_query_error_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 ff193155129e..61b114a6a65f 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -732,6 +732,8 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_LIST_LESSEES, drm_mode_list_lessees_ioctl, DRM_MASTER),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE, drm_mode_get_lease_ioctl, DRM_MASTER),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_REVOKE_LEASE, drm_mode_revoke_lease_ioctl, DRM_MASTER),
+	DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_QUERY_ERROR, drm_syncobj_query_error_ioctl,
+		      DRM_RENDER_ALLOW),
 };
 
 #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE(drm_ioctls)
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 2d4ab745fdad..2152cd029070 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -1717,3 +1717,25 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
 
 	return ret;
 }
+
+int drm_syncobj_query_error_ioctl(struct drm_device *dev, void *data,
+			    struct drm_file *file_private)
+{
+	struct drm_syncobj_error *args = data;
+	struct dma_fence *fence;
+	int ret;
+
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		return -EOPNOTSUPP;
+
+	ret = drm_syncobj_find_fence(file_private, args->handle, args->point, 0, &fence);
+
+	if (ret)
+		return ret;
+
+	args->error = fence->error;
+
+	dma_fence_put(fence);
+
+	return 0;
+}
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 27cc159c1d27..087c0f2120ec 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -1051,6 +1051,11 @@ struct drm_syncobj_timeline_array {
 	__u32 flags;
 };
 
+struct drm_syncobj_error {
+	__u32 handle;
+	__s32 error;
+	__u64 point;
+};
 
 /* Query current scanout sequence number */
 struct drm_crtc_get_sequence {
@@ -1363,6 +1368,14 @@ extern "C" {
  */
 #define DRM_IOCTL_GEM_CHANGE_HANDLE    DRM_IOWR(0xD2, struct drm_gem_change_handle)
 
+/**
+ * DRM_IOCTL_SYNCOBJ_QUERY_ERROR - Query the error code from a failed drm_syncobj
+ *
+ * This ioctl provides userspace a way to query the error code of a binary and
+ * timeline drm_syncobj in the case that the submission fails.
+ */
+#define DRM_IOCTL_SYNCOBJ_QUERY_ERROR	DRM_IOWR(0xD3, struct drm_syncobj_error)
+
 /*
  * Device specific ioctls should only be in their respective headers
  * The device specific ioctl range is from 0x40 to 0x9f.
-- 
2.53.0