Make some tweaks to the RealTek driver:

- Fix a bug in rl_rxeof() handler: in the case where the packet wraps
  from the end of the receive buffer back to the beginning, we need to
  insure that at least sizeof(ether_header) bytes make it into the first
  mbuf. If we don't, then doing eh = mtod(m, struct ether_header *)
  loses. To avoid this, we use m_pullup() to suck at least MHLEN -
  RL_ETHER_ALIGN bytes into the first mbuf, which should also help
  small packets fit into a single mbuf.

  Pointed out by: Philip A. Prindeville <philipp@zembu.com>

- Make the transmit threshold autotuning: start off with a small value
  and jack it up when TX underruns are detected.

- Also improve TX error recovery: kick the chip in the head with a
  reset/init sequence to make sure it recovers afer a transmit error.

2 files changed, 28 insertions, 12 deletions

diff --git a/sys/pci/if_rl.c b/sys/pci/if_rl.c
index a2e789d..bd90b70 100644
--- a/sys/pci/if_rl.c
+++ b/sys/pci/if_rl.c
@@ -988,7 +988,7 @@ static int rl_detach(dev)
 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->rl_res);
 	bus_release_resource(dev, RL_RES, RL_RID, sc->rl_res);
 
-	free(sc->rl_cdata.rl_rx_buf, M_DEVBUF);
+	contigfree(sc->rl_cdata.rl_rx_buf, RL_RXBUFLEN + 32, M_DEVBUF);
 
 	splx(s);
 
@@ -1125,12 +1125,12 @@ static void rl_rxeof(sc)
 			if (m == NULL) {
 				ifp->if_ierrors++;
 				printf("rl%d: out of mbufs, tried to "
-					"copy %d bytes\n", sc->rl_unit, wrap);
-			}
-			else {
+				    "copy %d bytes\n", sc->rl_unit, wrap);
+			} else {
 				m_adj(m, RL_ETHER_ALIGN);
 				m_copyback(m, wrap, total_len - wrap,
 					sc->rl_cdata.rl_rx_buf);
+				m_pullup(m, MHLEN - RL_ETHER_ALIGN);
 			}
 			cur_rx = (total_len - wrap + ETHER_CRC_LEN);
 		} else {
@@ -1139,7 +1139,7 @@ static void rl_rxeof(sc)
 			if (m == NULL) {
 				ifp->if_ierrors++;
 				printf("rl%d: out of mbufs, tried to "
-				"copy %d bytes\n", sc->rl_unit, total_len);
+				    "copy %d bytes\n", sc->rl_unit, total_len);
 			} else
 				m_adj(m, RL_ETHER_ALIGN);
 			cur_rx += total_len + 4 + ETHER_CRC_LEN;
@@ -1216,10 +1216,22 @@ static void rl_txeof(sc)
 		if (txstat & RL_TXSTAT_TX_OK)
 			ifp->if_opackets++;
 		else {
+			int			oldthresh;
 			ifp->if_oerrors++;
 			if ((txstat & RL_TXSTAT_TXABRT) ||
 			    (txstat & RL_TXSTAT_OUTOFWIN))
 				CSR_WRITE_4(sc, RL_TXCFG, RL_TXCFG_CONFIG);
+			oldthresh = sc->rl_txthresh;
+			/* error recovery */
+			rl_reset(sc);
+			rl_init(sc);
+			/*
+			 * If there was a transmit underrun,
+			 * bump the TX threshold.
+			 */
+			if (txstat & RL_TXSTAT_TX_UNDERRUN)
+				sc->rl_txthresh = oldthresh + 32;
+			return;
 		}
 		RL_INC(sc->rl_cdata.last_tx);
 		ifp->if_flags &= ~IFF_OACTIVE;
@@ -1290,9 +1302,8 @@ static void rl_intr(arg)
 	/* Re-enable interrupts. */
 	CSR_WRITE_2(sc, RL_IMR, RL_INTRS);
 
-	if (ifp->if_snd.ifq_head != NULL) {
+	if (ifp->if_snd.ifq_head != NULL)
 		rl_start(ifp);
-	}
 
 	return;
 }
@@ -1327,8 +1338,7 @@ static int rl_encap(sc, m_head)
 			return(1);
 		}
 	}
-	m_copydata(m_head, 0, m_head->m_pkthdr.len,	
-				mtod(m_new, caddr_t));
+	m_copydata(m_head, 0, m_head->m_pkthdr.len, mtod(m_new, caddr_t));
 	m_new->m_pkthdr.len = m_new->m_len = m_head->m_pkthdr.len;
 	m_freem(m_head);
 	m_head = m_new;
@@ -1336,7 +1346,7 @@ static int rl_encap(sc, m_head)
 	/* Pad frames to at least 60 bytes. */
 	if (m_head->m_pkthdr.len < RL_MIN_FRAMELEN) {
 		m_head->m_pkthdr.len +=
-			(RL_MIN_FRAMELEN - m_head->m_pkthdr.len);
+		    (RL_MIN_FRAMELEN - m_head->m_pkthdr.len);
 		m_head->m_len = m_head->m_pkthdr.len;
 	}
 
@@ -1377,7 +1387,8 @@ static void rl_start(ifp)
 		CSR_WRITE_4(sc, RL_CUR_TXADDR(sc),
 		    vtophys(mtod(RL_CUR_TXMBUF(sc), caddr_t)));
 		CSR_WRITE_4(sc, RL_CUR_TXSTAT(sc),
-		    RL_TX_EARLYTHRESH | RL_CUR_TXMBUF(sc)->m_pkthdr.len);
+		    RL_TXTHRESH(sc->rl_txthresh) |
+		    RL_CUR_TXMBUF(sc)->m_pkthdr.len);
 
 		RL_INC(sc->rl_cdata.cur_tx);
 	}
@@ -1472,6 +1483,9 @@ static void rl_init(xsc)
 	 */
 	CSR_WRITE_2(sc, RL_IMR, RL_INTRS);
 
+	/* Set initial TX threshold */
+	sc->rl_txthresh = RL_TX_THRESH_INIT;
+
 	/* Start RX/TX process. */
 	CSR_WRITE_4(sc, RL_MISSEDPKT, 0);
 
diff --git a/sys/pci/if_rlreg.h b/sys/pci/if_rlreg.h
index 8654f7e..0bb9ffc 100644
--- a/sys/pci/if_rlreg.h
+++ b/sys/pci/if_rlreg.h
@@ -299,7 +299,8 @@
 #define RL_RXBUFLEN		(1 << ((RL_RX_BUF_SZ >> 11) + 13))
 #define RL_TX_LIST_CNT		4
 #define RL_MIN_FRAMELEN		60
-#define RL_TX_EARLYTHRESH	(256 << 11)
+#define RL_TXTHRESH(x)		((x) << 11)
+#define RL_TX_THRESH_INIT	96
 #define RL_RX_FIFOTHRESH	RL_RXFIFO_256BYTES
 #define RL_RX_MAXDMA		RL_RXDMA_UNLIMITED
 #define RL_TX_MAXDMA		RL_TXDMA_2048BYTES
@@ -364,6 +365,7 @@ struct rl_softc {
 	u_int8_t		rl_unit;	/* interface number */
 	u_int8_t		rl_type;
 	u_int8_t		rl_stats_no_timeout;
+	int			rl_txthresh;
 	struct rl_chain_data	rl_cdata;
 	struct callout_handle	rl_stat_ch;
 };