summaryrefslogtreecommitdiffstats
path: root/include/uapi/drm/i915_drm.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/uapi/drm/i915_drm.h')
-rw-r--r--include/uapi/drm/i915_drm.h43
1 files changed, 35 insertions, 8 deletions
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index acf2102..a5524cc 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -772,10 +772,12 @@ struct drm_i915_gem_execbuffer2 {
#define I915_EXEC_HANDLE_LUT (1<<12)
/** Used for switching BSD rings on the platforms with two BSD rings */
-#define I915_EXEC_BSD_MASK (3<<13)
-#define I915_EXEC_BSD_DEFAULT (0<<13) /* default ping-pong mode */
-#define I915_EXEC_BSD_RING1 (1<<13)
-#define I915_EXEC_BSD_RING2 (2<<13)
+#define I915_EXEC_BSD_SHIFT (13)
+#define I915_EXEC_BSD_MASK (3 << I915_EXEC_BSD_SHIFT)
+/* default ping-pong mode */
+#define I915_EXEC_BSD_DEFAULT (0 << I915_EXEC_BSD_SHIFT)
+#define I915_EXEC_BSD_RING1 (1 << I915_EXEC_BSD_SHIFT)
+#define I915_EXEC_BSD_RING2 (2 << I915_EXEC_BSD_SHIFT)
/** Tell the kernel that the batchbuffer is processed by
* the resource streamer.
@@ -812,10 +814,35 @@ struct drm_i915_gem_busy {
/** Handle of the buffer to check for busy */
__u32 handle;
- /** Return busy status (1 if busy, 0 if idle).
- * The high word is used to indicate on which rings the object
- * currently resides:
- * 16:31 - busy (r or r/w) rings (16 render, 17 bsd, 18 blt, etc)
+ /** Return busy status
+ *
+ * A return of 0 implies that the object is idle (after
+ * having flushed any pending activity), and a non-zero return that
+ * the object is still in-flight on the GPU. (The GPU has not yet
+ * signaled completion for all pending requests that reference the
+ * object.)
+ *
+ * The returned dword is split into two fields to indicate both
+ * the engines on which the object is being read, and the
+ * engine on which it is currently being written (if any).
+ *
+ * The low word (bits 0:15) indicate if the object is being written
+ * to by any engine (there can only be one, as the GEM implicit
+ * synchronisation rules force writes to be serialised). Only the
+ * engine for the last write is reported.
+ *
+ * The high word (bits 16:31) are a bitmask of which engines are
+ * currently reading from the object. Multiple engines may be
+ * reading from the object simultaneously.
+ *
+ * The value of each engine is the same as specified in the
+ * EXECBUFFER2 ioctl, i.e. I915_EXEC_RENDER, I915_EXEC_BSD etc.
+ * Note I915_EXEC_DEFAULT is a symbolic value and is mapped to
+ * the I915_EXEC_RENDER engine for execution, and so it is never
+ * reported as active itself. Some hardware may have parallel
+ * execution engines, e.g. multiple media engines, which are
+ * mapped to the same identifier in the EXECBUFFER2 ioctl and
+ * so are not separately reported for busyness.
*/
__u32 busy;
};
OpenPOWER on IntegriCloud