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

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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().
This commit is contained in:
wpaul 1999-08-24 03:19:45 +00:00
parent 10d42c8b30
commit 19a3e3add0
2 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
sys/pci/if_pn.c
View File

@ -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)

4
sys/pci/if_pnreg.h
View File

@ -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
/*