1.\" $NetBSD: le.4,v 1.22 2004/10/04 19:12:52 rumble Exp $
2.\"
3.\"-
4.\" Copyright (c) 1992, 1993
5.\" The Regents of the University of California. All rights reserved.
6.\"
7.\" This software was developed by the Computer Systems Engineering group
8.\" at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9.\" contributed to Berkeley.
10.\"
11.\" Redistribution and use in source and binary forms, with or without
12.\" modification, are permitted provided that the following conditions
13.\" are met:
14.\" 1. Redistributions of source code must retain the above copyright
15.\" notice, this list of conditions and the following disclaimer.
16.\" 2. Redistributions in binary form must reproduce the above copyright
17.\" notice, this list of conditions and the following disclaimer in the
18.\" documentation and/or other materials provided with the distribution.
19.\" 3. Neither the name of the University nor the names of its contributors
20.\" may be used to endorse or promote products derived from this software
21.\" without specific prior written permission.
22.\"
23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33.\" SUCH DAMAGE.
34.\"
35.\" from: Header: le.4,v 1.2 92/10/13 05:31:33 leres Exp
36.\" from: @(#)le.4 8.1 (Berkeley) 6/9/93
| 1.\" $NetBSD: le.4,v 1.22 2004/10/04 19:12:52 rumble Exp $
2.\"
3.\"-
4.\" Copyright (c) 1992, 1993
5.\" The Regents of the University of California. All rights reserved.
6.\"
7.\" This software was developed by the Computer Systems Engineering group
8.\" at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9.\" contributed to Berkeley.
10.\"
11.\" Redistribution and use in source and binary forms, with or without
12.\" modification, are permitted provided that the following conditions
13.\" are met:
14.\" 1. Redistributions of source code must retain the above copyright
15.\" notice, this list of conditions and the following disclaimer.
16.\" 2. Redistributions in binary form must reproduce the above copyright
17.\" notice, this list of conditions and the following disclaimer in the
18.\" documentation and/or other materials provided with the distribution.
19.\" 3. Neither the name of the University nor the names of its contributors
20.\" may be used to endorse or promote products derived from this software
21.\" without specific prior written permission.
22.\"
23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33.\" SUCH DAMAGE.
34.\"
35.\" from: Header: le.4,v 1.2 92/10/13 05:31:33 leres Exp
36.\" from: @(#)le.4 8.1 (Berkeley) 6/9/93
|
37.\" $FreeBSD: head/share/man/man4/le.4 155153 2006-01-31 22:40:25Z marius $
| 37.\" $FreeBSD: head/share/man/man4/le.4 155220 2006-02-02 14:57:00Z marius $
|
38.\"
39.Dd January 30, 2006
40.Dt LE 4
41.Os
42.Sh NAME
43.Nm le
44.Nd "AMD Am7900 LANCE and Am79C9xx PCnet Ethernet interface driver"
45.Sh SYNOPSIS
46To compile this driver into the kernel,
47place the following line in your
48kernel configuration file:
49.Bd -ragged -offset indent
50.Cd "device le"
51.Ed
52.Pp
53Alternatively, to load the driver as a
54module at boot time, place the following line in
55.Xr loader.conf 5 :
56.Bd -literal -offset indent
57if_le_load="YES"
58.Ed
59.\" .Pp
60.\" In
61.\" .Pa /boot/device.hints :
62.\" .Cd hint.le.0.at="isa"
63.\" .Cd hint.le.0.port="0x280"
64.\" .Cd hint.le.0.irq="10"
65.\" .Cd hint.le.0.drq="0"
66.Sh DESCRIPTION
67The
68.Nm
69driver provides support for Ethernet adapters based on the
70.Tn AMD
71Am7990 and Am79C90 (CMOS, pin-compatible)
72Local Area Network Controller for Ethernet
73.Pq Tn LANCE
74chip set.
75.Pp
76The
77.Nm
78driver also supports PCnet adapters based on the
79.Tn AMD 79C9xx
80family of chips, which are single-chip implementations of a
81.Tn LANCE
| 38.\"
39.Dd January 30, 2006
40.Dt LE 4
41.Os
42.Sh NAME
43.Nm le
44.Nd "AMD Am7900 LANCE and Am79C9xx PCnet Ethernet interface driver"
45.Sh SYNOPSIS
46To compile this driver into the kernel,
47place the following line in your
48kernel configuration file:
49.Bd -ragged -offset indent
50.Cd "device le"
51.Ed
52.Pp
53Alternatively, to load the driver as a
54module at boot time, place the following line in
55.Xr loader.conf 5 :
56.Bd -literal -offset indent
57if_le_load="YES"
58.Ed
59.\" .Pp
60.\" In
61.\" .Pa /boot/device.hints :
62.\" .Cd hint.le.0.at="isa"
63.\" .Cd hint.le.0.port="0x280"
64.\" .Cd hint.le.0.irq="10"
65.\" .Cd hint.le.0.drq="0"
66.Sh DESCRIPTION
67The
68.Nm
69driver provides support for Ethernet adapters based on the
70.Tn AMD
71Am7990 and Am79C90 (CMOS, pin-compatible)
72Local Area Network Controller for Ethernet
73.Pq Tn LANCE
74chip set.
75.Pp
76The
77.Nm
78driver also supports PCnet adapters based on the
79.Tn AMD 79C9xx
80family of chips, which are single-chip implementations of a
81.Tn LANCE
|
82chip and
| 82chip and a DMA engine.
83This includes a superset of the
|
83.Tn PCI
| 84.Tn PCI
|
84bus interface.
85This includes most of the adapters which are also supported by the
| 85bus Ethernet chip sets supported by the
|
86.Xr pcn 4
87driver.
88The
89.Nm
| 86.Xr pcn 4
87driver.
88The
89.Nm
|
90driver does not support all features of these adapters however, thus the
| 90driver treats all of these
91.Tn PCI
92bus Ethernet chip sets as an
93.Tn AMD Am79C970 PCnet-PCI
94and does not support the additional features like the MII bus and burst mode of
95.Tn AMD Am79C971 PCnet-FAST
96and greater chip sets.
97Thus the
|
91.Xr pcn 4
| 98.Xr pcn 4
|
92driver should be preferred.
| 99driver should be preferred for the latter.
|
93.Pp
94The
95.Nm
96driver supports reception and transmission of extended frames for
97.Xr vlan 4 .
98Selective reception of multicast Ethernet frames is provided by a 64-bit mask;
99multicast destination addresses are hashed to a bit entry using the Ethernet
100CRC function.
101.Sh HARDWARE
102.\" .Ss ISA
103.\" The
104.\" .Tn ISA
105.\" bus Ethernet cards supported by the
106.\" .Nm
107.\" driver are:
108.\" .Pp
109.\" .Bl -bullet -compact
110.\" .It
111.\" .Tn BICC Isolan
112.\" .It
113.\" .Tn Novell NE2100
114.\" .It
115.\" .Tn Digital DEPCA
116.\" .El
117.\" .Ss EISA
118.\" The
119.\" .Tn EISA
120.\" bus Ethernet cards supported by the
121.\" .Nm
122.\" driver are:
123.\" .Pp
124.\" .Bl -bullet -compact
125.\" .It
126.\" .Tn DEC DE422
127.\" .El
128.\" .Ss MCA
129.\" The
130.\" .Tn MCA
131.\" bus Ethernet cards supported by the
132.\" .Nm
133.\" driver are:
134.\" .Pp
135.\" .Bl -bullet -compact
136.\" .It
137.\" .Tn SKNET Personal MC2
138.\" .It
139.\" .Tn SKNET MC2+
140.\" .El
141.Ss PCI
142The
143.Tn PCI
144bus Ethernet chip sets supported by the
145.Nm
146driver are:
147.Pp
148.Bl -bullet -compact
149.It
150.Tn AMD Am53C974/Am79C970/Am79C974 PCnet-PCI
151.It
152.Tn AMD Am79C970A PCnet-PCI II
153.It
154.Tn AMD Am79C971 PCnet-FAST
155.It
156.Tn AMD Am79C972 PCnet-FAST+
157.It
158.Tn AMD Am79C973/Am79C975 PCnet-FAST III
159.It
160.Tn AMD Am79C976 PCnet-PRO
161.It
162.Tn AMD Am79C978 PCnet-Home
163.El
164.Pp
165The
166.Nm
167driver supports the following media types with these chip sets:
168.Pp
169.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
170.It autoselect
171Enable autoselection of the media type.
172.It 10baseT/UTP
173Select UTP media.
174.It 10base5/AUI
175Select AUI/BNC media.
176.El
177.Pp
178The following media option is supported with these media types:
179.Pp
180.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
181.It full-duplex
182Select full duplex operation.
183.El
184.Pp
185Note that unlike the
186.Xr pcn 4
187driver, the
188.Nm
189driver does not support selecting 100Mbps (Fast Ethernet) media types.
190.Ss sparc64
191The
192.Nm
193driver supports the on-board
194.Tn LANCE
195interfaces found in
196.Tn Sun Ultra 1
197machines.
198The following media types are available with these:
199.Pp
200.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
201.It autoselect
202Enable autoselection of the media type.
203.It 10baseT/UTP
204Select UTP media.
205.It 10base5/AUI
206Select AUI media.
207.El
208.Pp
209When using autoselection, a default media type is selected for use by
210examining all ports for carrier.
211The first media type with which a carrier is detected will be selected.
212Additionally, if carrier is dropped on a port, the driver will switch
213between the possible ports until one with carrier is found.
214.\" .Pp
215.\" The
216.\" .Nm
217.\" driver also supports
218.\" .Tn SBus
219.\" Ethernet cards.
220.\" These include:
221.\" .Bl -bullet -compact
222.\" .It
223.\" SBE/S
224.\" .Tn SCSI
225.\" and Buffered Ethernet
226.\" (Sun P/N 501-1860)
227.\" .It
228.\" FSBE/S
229.\" Fast
230.\" .Tn SCSI
231.\" and Buffered Ethernet
232.\" (Sun P/N 501-2015)
233.\" .El
234.Pp
235For further information on configuring media types and options, see
236.Xr ifconfig 8 .
237.Sh DIAGNOSTICS
238.Bl -diag
239.It "le%d: overflow"
240More packets came in from the Ethernet than there was space in the
241.Tn LANCE
242receive buffers.
243Packets were missed.
244.It "le%d: receive buffer error"
245The
246.Tn LANCE
247ran out of buffer space, packet dropped.
248.It "le%d: lost carrier"
249The Ethernet carrier disappeared during an attempt to transmit.
250The
251.Tn LANCE
252will finish transmitting the current packet,
253but will not automatically retry transmission if there is a collision.
254.It "le%d: excessive collisions, tdr %d"
255The Ethernet was extremely busy or jammed,
256outbound packets were dropped after 16 attempts to retransmit.
257.Pp
258TDR
259is the abbreviation of
260.Qq Time Domain Reflectometry .
261The optionally reported TDR value is an internal counter of the interval
262between the start of a transmission and the occurrence of a collision.
263This value can be used to determine the distance from the Ethernet tap to
264the point on the Ethernet cable that is shorted or open (unterminated).
265.It "le%d: dropping chained buffer"
266A packet did not fit into a single receive buffer and was dropped.
267Since the
268.Nm
269driver allocates buffers large enough to receive maximum sized Ethernet
270packets, this means some other station on the LAN transmitted a packet
271larger than allowed by the Ethernet standard.
272.It "le%d: transmit buffer error"
273The
274.Tn LANCE
275ran out of buffer space before finishing the transmission of a packet.
276If this error occurs, the driver software has a bug.
277.It "le%d: underflow"
278The
279.Tn LANCE
280ran out of buffer space before finishing the transmission of a packet.
281If this error occurs, the driver software has a bug.
282.It "le%d: controller failed to initialize"
283Driver failed to start the
284.Tn LANCE .
285This is potentially a hardware failure.
286.It "le%d: memory error"
287RAM failed to respond within the timeout when the
288.Tn LANCE
289wanted to read or write it.
290This is potentially a hardware failure.
291.It "le%d: receiver disabled"
292The receiver of the
293.Tn LANCE
294was turned off due to an error.
295.It "le%d: transmitter disabled"
296The transmitter of the
297.Tn LANCE
298was turned off due to an error.
299.El
300.Sh SEE ALSO
301.Xr arp 4 ,
302.Xr intro 4 ,
303.Xr netintro 4 ,
304.Xr pcn 4 ,
305.Xr vlan 4 ,
306.Xr ifconfig 8
307.Sh HISTORY
308The
309.Nm
310driver was ported from
311.Nx
312and first appeared in
313.Fx 6.1 .
314The
315.Nx
316version in turn was derived from the
317.Nm
318driver which first appeared in
319.Bx 4.4 .
320.Sh AUTHORS
321The
322.Nm
323driver was ported by
324.An "Marius Strobl" Aq marius@FreeBSD.org .
325.\" .Sh BUGS
326.\" The Am7990 Revision C chips have a bug which causes garbage to be inserted
327.\" in front of the received packet occasionally.
328.\" The work-around is to ignore packets with an invalid destination address
329.\" (garbage will usually not match), by double-checking the destination
330.\" address of every packet in the driver.
331.\" This work-around can be enabled with the
332.\" .Dv LANCE_REVC_BUG
333.\" kernel option.
334.\" .Pp
335.\" When
336.\" .Dv LANCE_REVC_BUG
337.\" is enabled, the
338.\" .Nm
339.\" driver executes one or two calls to an inline Ethernet address comparison
340.\" function for every received packet.
341.\" On the
342.\" .Tn MC68000
343.\" it is exactly eight instructions of 16 bits each.
344.\" There is one comparison for each unicast packet, and two comparisons for
345.\" each broadcast packet.
346.\" .Pp
347.\" In summary, the cost of the LANCE_REVC_BUG option is:
348.\" .Bl -enum -compact
349.\" .It
350.\" loss of multicast support, and
351.\" .It
352.\" eight extra
353.\" .Tn CPU
354.\" instructions per received packet, sometimes sixteen, depending on both the
355.\" processor, and the type of packet.
356.\" .El
357.\" .Pp
358.\" All sun3 systems are presumed to have this bad revision of the Am7990,
359.\" until proven otherwise.
360.\" Alas, the only way to prove what revision of the chip is in a particular
361.\" system is inspection of the date code on the chip package,
362.\" to compare against a list of what chip revisions were fabricated between
363.\" which dates.
364.\" .Pp
365.\" Alas, the Am7990 chip is so old that
366.\" .Tn AMD
367.\" has
368.\" .Qq de-archived
369.\" the production information about it; pending a search elsewhere, we do not
370.\" know how to identify the revision C chip from the date codes.
| 100.Pp
101The
102.Nm
103driver supports reception and transmission of extended frames for
104.Xr vlan 4 .
105Selective reception of multicast Ethernet frames is provided by a 64-bit mask;
106multicast destination addresses are hashed to a bit entry using the Ethernet
107CRC function.
108.Sh HARDWARE
109.\" .Ss ISA
110.\" The
111.\" .Tn ISA
112.\" bus Ethernet cards supported by the
113.\" .Nm
114.\" driver are:
115.\" .Pp
116.\" .Bl -bullet -compact
117.\" .It
118.\" .Tn BICC Isolan
119.\" .It
120.\" .Tn Novell NE2100
121.\" .It
122.\" .Tn Digital DEPCA
123.\" .El
124.\" .Ss EISA
125.\" The
126.\" .Tn EISA
127.\" bus Ethernet cards supported by the
128.\" .Nm
129.\" driver are:
130.\" .Pp
131.\" .Bl -bullet -compact
132.\" .It
133.\" .Tn DEC DE422
134.\" .El
135.\" .Ss MCA
136.\" The
137.\" .Tn MCA
138.\" bus Ethernet cards supported by the
139.\" .Nm
140.\" driver are:
141.\" .Pp
142.\" .Bl -bullet -compact
143.\" .It
144.\" .Tn SKNET Personal MC2
145.\" .It
146.\" .Tn SKNET MC2+
147.\" .El
148.Ss PCI
149The
150.Tn PCI
151bus Ethernet chip sets supported by the
152.Nm
153driver are:
154.Pp
155.Bl -bullet -compact
156.It
157.Tn AMD Am53C974/Am79C970/Am79C974 PCnet-PCI
158.It
159.Tn AMD Am79C970A PCnet-PCI II
160.It
161.Tn AMD Am79C971 PCnet-FAST
162.It
163.Tn AMD Am79C972 PCnet-FAST+
164.It
165.Tn AMD Am79C973/Am79C975 PCnet-FAST III
166.It
167.Tn AMD Am79C976 PCnet-PRO
168.It
169.Tn AMD Am79C978 PCnet-Home
170.El
171.Pp
172The
173.Nm
174driver supports the following media types with these chip sets:
175.Pp
176.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
177.It autoselect
178Enable autoselection of the media type.
179.It 10baseT/UTP
180Select UTP media.
181.It 10base5/AUI
182Select AUI/BNC media.
183.El
184.Pp
185The following media option is supported with these media types:
186.Pp
187.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
188.It full-duplex
189Select full duplex operation.
190.El
191.Pp
192Note that unlike the
193.Xr pcn 4
194driver, the
195.Nm
196driver does not support selecting 100Mbps (Fast Ethernet) media types.
197.Ss sparc64
198The
199.Nm
200driver supports the on-board
201.Tn LANCE
202interfaces found in
203.Tn Sun Ultra 1
204machines.
205The following media types are available with these:
206.Pp
207.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
208.It autoselect
209Enable autoselection of the media type.
210.It 10baseT/UTP
211Select UTP media.
212.It 10base5/AUI
213Select AUI media.
214.El
215.Pp
216When using autoselection, a default media type is selected for use by
217examining all ports for carrier.
218The first media type with which a carrier is detected will be selected.
219Additionally, if carrier is dropped on a port, the driver will switch
220between the possible ports until one with carrier is found.
221.\" .Pp
222.\" The
223.\" .Nm
224.\" driver also supports
225.\" .Tn SBus
226.\" Ethernet cards.
227.\" These include:
228.\" .Bl -bullet -compact
229.\" .It
230.\" SBE/S
231.\" .Tn SCSI
232.\" and Buffered Ethernet
233.\" (Sun P/N 501-1860)
234.\" .It
235.\" FSBE/S
236.\" Fast
237.\" .Tn SCSI
238.\" and Buffered Ethernet
239.\" (Sun P/N 501-2015)
240.\" .El
241.Pp
242For further information on configuring media types and options, see
243.Xr ifconfig 8 .
244.Sh DIAGNOSTICS
245.Bl -diag
246.It "le%d: overflow"
247More packets came in from the Ethernet than there was space in the
248.Tn LANCE
249receive buffers.
250Packets were missed.
251.It "le%d: receive buffer error"
252The
253.Tn LANCE
254ran out of buffer space, packet dropped.
255.It "le%d: lost carrier"
256The Ethernet carrier disappeared during an attempt to transmit.
257The
258.Tn LANCE
259will finish transmitting the current packet,
260but will not automatically retry transmission if there is a collision.
261.It "le%d: excessive collisions, tdr %d"
262The Ethernet was extremely busy or jammed,
263outbound packets were dropped after 16 attempts to retransmit.
264.Pp
265TDR
266is the abbreviation of
267.Qq Time Domain Reflectometry .
268The optionally reported TDR value is an internal counter of the interval
269between the start of a transmission and the occurrence of a collision.
270This value can be used to determine the distance from the Ethernet tap to
271the point on the Ethernet cable that is shorted or open (unterminated).
272.It "le%d: dropping chained buffer"
273A packet did not fit into a single receive buffer and was dropped.
274Since the
275.Nm
276driver allocates buffers large enough to receive maximum sized Ethernet
277packets, this means some other station on the LAN transmitted a packet
278larger than allowed by the Ethernet standard.
279.It "le%d: transmit buffer error"
280The
281.Tn LANCE
282ran out of buffer space before finishing the transmission of a packet.
283If this error occurs, the driver software has a bug.
284.It "le%d: underflow"
285The
286.Tn LANCE
287ran out of buffer space before finishing the transmission of a packet.
288If this error occurs, the driver software has a bug.
289.It "le%d: controller failed to initialize"
290Driver failed to start the
291.Tn LANCE .
292This is potentially a hardware failure.
293.It "le%d: memory error"
294RAM failed to respond within the timeout when the
295.Tn LANCE
296wanted to read or write it.
297This is potentially a hardware failure.
298.It "le%d: receiver disabled"
299The receiver of the
300.Tn LANCE
301was turned off due to an error.
302.It "le%d: transmitter disabled"
303The transmitter of the
304.Tn LANCE
305was turned off due to an error.
306.El
307.Sh SEE ALSO
308.Xr arp 4 ,
309.Xr intro 4 ,
310.Xr netintro 4 ,
311.Xr pcn 4 ,
312.Xr vlan 4 ,
313.Xr ifconfig 8
314.Sh HISTORY
315The
316.Nm
317driver was ported from
318.Nx
319and first appeared in
320.Fx 6.1 .
321The
322.Nx
323version in turn was derived from the
324.Nm
325driver which first appeared in
326.Bx 4.4 .
327.Sh AUTHORS
328The
329.Nm
330driver was ported by
331.An "Marius Strobl" Aq marius@FreeBSD.org .
332.\" .Sh BUGS
333.\" The Am7990 Revision C chips have a bug which causes garbage to be inserted
334.\" in front of the received packet occasionally.
335.\" The work-around is to ignore packets with an invalid destination address
336.\" (garbage will usually not match), by double-checking the destination
337.\" address of every packet in the driver.
338.\" This work-around can be enabled with the
339.\" .Dv LANCE_REVC_BUG
340.\" kernel option.
341.\" .Pp
342.\" When
343.\" .Dv LANCE_REVC_BUG
344.\" is enabled, the
345.\" .Nm
346.\" driver executes one or two calls to an inline Ethernet address comparison
347.\" function for every received packet.
348.\" On the
349.\" .Tn MC68000
350.\" it is exactly eight instructions of 16 bits each.
351.\" There is one comparison for each unicast packet, and two comparisons for
352.\" each broadcast packet.
353.\" .Pp
354.\" In summary, the cost of the LANCE_REVC_BUG option is:
355.\" .Bl -enum -compact
356.\" .It
357.\" loss of multicast support, and
358.\" .It
359.\" eight extra
360.\" .Tn CPU
361.\" instructions per received packet, sometimes sixteen, depending on both the
362.\" processor, and the type of packet.
363.\" .El
364.\" .Pp
365.\" All sun3 systems are presumed to have this bad revision of the Am7990,
366.\" until proven otherwise.
367.\" Alas, the only way to prove what revision of the chip is in a particular
368.\" system is inspection of the date code on the chip package,
369.\" to compare against a list of what chip revisions were fabricated between
370.\" which dates.
371.\" .Pp
372.\" Alas, the Am7990 chip is so old that
373.\" .Tn AMD
374.\" has
375.\" .Qq de-archived
376.\" the production information about it; pending a search elsewhere, we do not
377.\" know how to identify the revision C chip from the date codes.
|