1.\" $NetBSD: ec.4,v 1.14 2017/07/03 21:30:58 wiz Exp $ 2.\" 3.\" Copyright (c) 1997 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 8.\" NASA Ames Research Center. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29.\" POSSIBILITY OF SUCH DAMAGE. 30.\" 31.Dd October 20, 1997 32.Dt EC 4 33.Os 34.Sh NAME 35.Nm ec 36.Nd driver for 3Com EtherLink II (3c503) 37.Tn ISA 38bus 39.Tn Ethernet 40cards 41.Sh SYNOPSIS 42.Cd "ec0 at isa? port 0x250 iomem 0xd8000 irq 9" 43.Sh DESCRIPTION 44The 45.Nm 46device driver supports 3Com EtherLink II (3c503) 47.Tn Ethernet 48cards for 49.Tn ISA 50bus which are based on the National Semiconductor DP8390/WD83C690 51.Tn Ethernet 52interface chips. 53.Sh MEDIA SELECTION 54The EtherLink II supports two media types on a single card. 55All support the 56.Tn AUI 57media type. 58The other media is either 59.Tn BNC 60or 61.Tn UTP 62behind a transceiver. 63Software cannot differentiate between 64.Tn BNC 65and 66.Tn UTP 67cards. 68.Pp 69To enable the AUI media, select the 70.Em 10base5 71or 72.Em aui 73media type with 74.Xr ifconfig 8 Ns 's 75.Cm media 76directive. 77To select the other media 78.Po 79.Tn BNC 80or 81.Tn UTP 82.Pc , 83select the 84.Em 10base2 85or 86.Em bnc 87media type. 88.Sh DIAGNOSTICS 89.Bl -diag 90.It "ec0: wildcarded IRQ is not allowed" 91.Pp 92The 93.Tn IRQ 94was wildcarded in the kernel configuration file. 95This is not supported. 96.It "ec0: invalid IRQ <n>, must be 3, 4, 5, or 9" 97.Pp 98An 99.Tn IRQ 100other than the above 101.Tn IRQ 102values was specified in the kernel configuration file. 103The EtherLink II hardware only supports the above listed 104.Tn IRQ 105values. 106.It "ec0: failed to clear shared memory at offset <off>" 107.Pp 108The memory test was unable to clear shared the interface's shared memory 109region. 110This often indicates that the card is configured at a conflicting 111.Em iomem 112address. 113.It "ec0: warning - receiver ring buffer overrun" 114.Pp 115The DP8390 116.Tn Ethernet 117chip used by this board implements a shared-memory 118ring-buffer to store incoming packets. 119The 3c503 usually has only 8K bytes of shared memory. 120This is only enough room for about 4 full-size (1500 byte) packets. 121This can sometimes be a problem, especially on the original 3c503, because 122these boards' shared-memory access speed is quite slow; typically only 123about 1MB/second. 124The overhead of this slow memory access, and the fact that there 125is only room for 4 full-sized packets means that the ring-buffer 126will occasionally overrun. 127.Pp 128When an overrun occurs, the board must be reset to avoid a lockup 129problem in early revision DP8390 130.Tn Ethernet 131chips. 132Resetting the board causes all of the data in the ring-buffer to be 133lost, requiring the data to be retransmitted/received, congesting the board 134further. 135Because of this, maximum throughput on these boards is only about 136400-600K bytes per second. 137.Pp 138This problem is exacerbated by 139.Tn NFS 140because the 8-bit boards lack sufficient packet buffer memory to 141support the default 8K byte packets that 142.Tn NFS 143and other protocols use as their default. 144If these cards must be used 145with 146.Tn NFS , 147use the 148.Xr mount_nfs 8 149.Fl \&r 150and 151.Fl \&w 152options in 153.Pa /etc/fstab 154to limit NFS's packet size. 1554K (4096) byte packets generally work. 156.El 157.Sh SEE ALSO 158.Xr ifmedia 4 , 159.Xr intro 4 , 160.Xr isa 4 , 161.Xr ifconfig 8 , 162.Xr mount_nfs 8 163