Change PN_RXLEN from 1518 bytes to 1536 bytes. The chip always DMAs data

in 4 byte chunks. It turns out that with the 82c169C on the Netgear
FA-310TX Rev D2, if you tell the chip you have reserved a buffer of 1518
bytes, it will actually treat it as 1516 bytes since 1518 is divisible
by four. Consequently, a packet of 1514 bytes will always end up consuming
two buffers: the last coupleof bytes will spill over into the next
descriptor. This causes the pn_rx_bug_war() routine to trip unnecessarily.

I'm not sure if the 82c169B or 82c168 chips behave the same way; I'll
have to check them. In any case, this change should work just as well
with them. Note that the FA-310TX Rev D2 also has a Broadcom PHY
instead of a Level One LXT970 PHY, however this shouldn't make any
difference as far as the driver is concerned.

This change also allows me to do a way with one rounding overation in
pn_rx-buf_war().

2 files changed, 6 insertions, 6 deletions

diff --git a/sys/pci/if_pn.c b/sys/pci/if_pn.c
index 20f968e..02d5a48 100644
--- a/sys/pci/if_pn.c
+++ b/sys/pci/if_pn.c
@@ -29,7 +29,7 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  *
- *	$Id: if_pn.c,v 1.53 1999/05/28 18:45:26 wpaul Exp wpaul $
+ *	$Id: if_pn.c,v 1.24 1999/07/28 02:19:51 wpaul Exp $
  */
 
 /*
@@ -105,7 +105,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-	"$Id: if_pn.c,v 1.53 1999/05/28 18:45:26 wpaul Exp wpaul $";
+	"$Id: if_pn.c,v 1.24 1999/07/28 02:19:51 wpaul Exp $";
 #endif
 
 /*
@@ -1158,7 +1158,7 @@ static int pn_attach(dev)
 	if (revision == PN_169B_REV || revision == PN_169_REV ||
 	    (revision & 0xF0) == PN_168_REV) {
 		sc->pn_rx_war = 1;
-		sc->pn_rx_buf = malloc(PN_RXLEN * 16, M_DEVBUF, M_NOWAIT);
+		sc->pn_rx_buf = malloc(PN_RXLEN * 5, M_DEVBUF, M_NOWAIT);
 		if (sc->pn_rx_buf == NULL) {
 			printf("pn%d: no memory for workaround buffer\n", unit);
 			bus_teardown_intr(dev, sc->pn_irq, sc->pn_intrhand);
@@ -1496,7 +1496,7 @@ static void pn_rx_bug_war(sc, cur_rx)
 	while ((c->pn_ptr->pn_status & PN_WHOLEFRAME) != PN_WHOLEFRAME) {
 		rxstat = c->pn_ptr->pn_status;
 		m_copydata(c->pn_mbuf, 0, PN_RXLEN, ptr);
-		ptr += PN_RXLEN - 2; /* round down to 32-bit boundary */
+		ptr += PN_RXLEN;
 		if (c == cur_rx)
 			break;
 		if (rxstat & PN_RXSTAT_LASTFRAG)
diff --git a/sys/pci/if_pnreg.h b/sys/pci/if_pnreg.h
index ce1294a..7072353 100644
--- a/sys/pci/if_pnreg.h
+++ b/sys/pci/if_pnreg.h
@@ -29,7 +29,7 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  *
- *	$Id: if_pnreg.h,v 1.27 1999/05/28 18:45:26 wpaul Exp wpaul $
+ *	$Id: if_pnreg.h,v 1.15 1999/07/28 02:19:52 wpaul Exp $
  */
 
 /*
@@ -393,7 +393,7 @@ struct pn_desc {
 #define PN_TX_LIST_CNT		128
 #define PN_MIN_FRAMELEN		60
 #define PN_FRAMELEN		1536
-#define PN_RXLEN		1518
+#define PN_RXLEN		1536
 #define ETHER_ALIGN		2
 
 /*