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-rw-r--r--drivers/net/ixgb/ixgb_main.c27
1 files changed, 6 insertions, 21 deletions
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 652c0eab3a4a..ecd5252c4bf4 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -146,14 +146,6 @@ static int debug = DEFAULT_DEBUG_LEVEL_SHIFT;
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
-/* some defines for controlling descriptor fetches in h/w */
-#define RXDCTL_WTHRESH_DEFAULT 15 /* chip writes back at this many or RXT0 */
-#define RXDCTL_PTHRESH_DEFAULT 0 /* chip considers prefech below
- * this */
-#define RXDCTL_HTHRESH_DEFAULT 0 /* chip will only prefetch if tail
- * is pushed this many descriptors
- * from head */
-
/**
* ixgb_init_module - Driver Registration Routine
*
@@ -839,7 +831,6 @@ ixgb_configure_rx(struct ixgb_adapter *adapter)
struct ixgb_hw *hw = &adapter->hw;
u32 rctl;
u32 rxcsum;
- u32 rxdctl;
/* make sure receives are disabled while setting up the descriptors */
@@ -861,18 +852,12 @@ ixgb_configure_rx(struct ixgb_adapter *adapter)
IXGB_WRITE_REG(hw, RDH, 0);
IXGB_WRITE_REG(hw, RDT, 0);
- /* set up pre-fetching of receive buffers so we get some before we
- * run out (default hardware behavior is to run out before fetching
- * more). This sets up to fetch if HTHRESH rx descriptors are avail
- * and the descriptors in hw cache are below PTHRESH. This avoids
- * the hardware behavior of fetching <=512 descriptors in a single
- * burst that pre-empts all other activity, usually causing fifo
- * overflows. */
- /* use WTHRESH to burst write 16 descriptors or burst when RXT0 */
- rxdctl = RXDCTL_WTHRESH_DEFAULT << IXGB_RXDCTL_WTHRESH_SHIFT |
- RXDCTL_HTHRESH_DEFAULT << IXGB_RXDCTL_HTHRESH_SHIFT |
- RXDCTL_PTHRESH_DEFAULT << IXGB_RXDCTL_PTHRESH_SHIFT;
- IXGB_WRITE_REG(hw, RXDCTL, rxdctl);
+ /* due to the hardware errata with RXDCTL, we are unable to use any of
+ * the performance enhancing features of it without causing other
+ * subtle bugs, some of the bugs could include receive length
+ * corruption at high data rates (WTHRESH > 0) and/or receive
+ * descriptor ring irregularites (particularly in hardware cache) */
+ IXGB_WRITE_REG(hw, RXDCTL, 0);
/* Enable Receive Checksum Offload for TCP and UDP */
if (adapter->rx_csum) {