fix comments

Author: pengxin99

va/va.h

@@ -4197,9 +4197,10 @@ Synchronization
  *   and verify its validity and integrity.
  * - \ref VA_STATUS_ERROR_OPERATION_FAILED: When the attempt to retrieve the status report fails or related work
  *   on the current surface fails, this error is generated. In such cases, the client can proceed with subsequent
- *   frames by ignore the error, but it may involve incorrect result like corruption.
+ *   frames by ignore the error, but it may involve incorrect result like corruption, MD5 mismatch or HW hang.
+ *   Initialize new context can avoid the potential issues.
  * - \ref VA_STATUS_ERROR_HW_BUSY: This error indicates that synchronization is still in progress or GPU hang happens.
- *   The client could call the function again within a period of time to wait hw execution completion.
+ *   The client could call the function again with the same render_target within a period of time to wait hw execution completion.
  *   If hw execution could not complete successfully, gpu hang and reset may occur, in this case,
  *   application could try to recover media context by initialing new one.
  * - \ref VA_STATUS_ERROR_DECODING_ERROR: This error is encountered when macroblock (MB) errors with