#define DEFAULT_RADV 8
#define BURST_RDTR 0x20
#define BURST_RADV 0x20
+#define PCICFG_DESC_RING_STATUS 0xe4
+#define FLUSH_DESC_REQUIRED 0x100
/* in the case of WTHRESH, it appears at least the 82571/2 hardware
* writes back 4 descriptors when WTHRESH=5, and 3 descriptors when