#define D3DLOCK_READONLY 0x00000010L
#define D3DLOCK_DISCARD 0x00002000L
#define D3DLOCK_NOOVERWRITE 0x00001000L
#define D3DLOCK_NOSYSLOCK 0x00000800L
#define D3DLOCK_DONOTWAIT 0x00004000L

#define D3DLOCK_NO_DIRTY_UPDATE 0x00008000L

これじゃなくて?