drm/xe/uapi: Document use of size in drm_xe_device_query

Document the behavior of the driver for IOCTL DRM_IOCTL_XE_DEVICE_QUERY depending on the size value provided in struct drm_xe_device_query.

Francois Dugast committed 2 years ago

Commit ff6c6bc1 parent 4efaadd1 file · +9 −3Browse files

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@@ -467,9 +467,15 @@ struct drm_xe_query_topology_mask { · 466 unmodified lines
467	467	* struct drm_xe_device_query - Input of &DRM_IOCTL_XE_DEVICE_QUERY - main
468	468	* structure to query device information
469	469	*
470		− * If size is set to 0, the driver fills it with the required size for the
471		− * requested type of data to query. If size is equal to the required size,
472		− * the queried information is copied into data.
	470	+ * The user selects the type of data to query among DRM_XE_DEVICE_QUERY_*
	471	+ * and sets the value in the query member. This determines the type of
	472	+ * the structure provided by the driver in data, among struct drm_xe_query_*.
	473	+ *
	474	+ * If size is set to 0, the driver fills it with the required size for
	475	+ * the requested type of data to query. If size is equal to the required
	476	+ * size, the queried information is copied into data. If size is set to
	477	+ * a value different from 0 and different from the required size, the
	478	+ * IOCTL call returns -EINVAL.
473	479	*
474	480	* For example the following code snippet allows retrieving and printing
475	481	* information about the device engines with DRM_XE_DEVICE_QUERY_ENGINES:

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