ED(4)

NAME
ed - high performance ethernet device driver

SYNOPSIS
device ed0 at isa? port 0x280 net irq 5 iomem 0xd8000 vector edintr
device ed1 at isa? port 0x300 net irq 5 iomem 0xd8000 vector edintr
device ed2 at isa? port 0x320 net irq 10 flags 0x4 iosiz 16384 iomem 0xd8000 vector edintr

DESCRIPTION
The ed driver provides support for 8 and 16bit ISA ethernet cards that are based on the National Semiconductor DS8390 and similar NICs manufactured by other companies.

It supports all 80x3 series ISA ethernet cards manufatured by Western Digital and SMC, the SMC Ultra, the 3Com 3c503, the Novell NE1000/NE2000, and HP PC Lan+.

The ed driver uses a unique multi-buffering mechanism to achieve high transmit performance. When using 16bit ISA cards, as high as 97% of the theoretical maximum performance of the IEEE 802.3 CSMA ethernet is possible.

In addition to the standard port and irq specifications, the ed driver also supports a number of flags which can force 8/16bit mode, enable/disable multi-buffering, and select the default interface type (AUI/BNC, and for cards with twisted pair, AUI/10BaseT).

The flags are a bit field, and are summerized as follows:

0x01
    Disable tranceiver. On those cards which support it, this flag causes the tranceiver to be disabled and the AUI connection to be used by default.

0x02
    Force 8bit mode. This flag forces the card to 8bit mode regardless of how the card identifies itself. This may be needed for some clones which incorrectly identify themselves as 16bit, even though they only have an 8bit interface.

0x04
    Force 16bit mode. This flag forces the card to 16bit mode regardless of how the card identifies itself. This may be needed for some clones which incorrectly identify themselves as 8bit, even though they have a 16bit ISA interface.

0x08
    Disable transmitter multi-buffering. This flag disables the use of multiple transmit buffers and may be necessary in rare cases where packets are sent out faster than a machine on the other end can handle (as evidenced by severe packet lossage). Some (non-FreeBSD :-)) machines have terrible ethernet performance and simply can't cope with 1100K+ data rates. Use of this flag also provides one more packet worth of receiver buffering, and on 8bit cards, this may help reduce receiver lossage.

When using a 3c503 card, the AUI connection may be selected by specifying the link2 option to ifconfig(8) (BNC is the default).

DIAGNOSTICS

ed%d: kernel configured irq %d doesn't match board configured irq %d. The irq number that was specified in the kernel config file (and then compiled into the kernel) differs from the irq that has been set on the interface card.

ed%d: failed to clear shared memory at %x - check configuration. When the card was probed at system boot time, the ed driver found that it could not clear the card's shared memory. This is most commonly caused by a BIOS extension ROM being configured in the same address space as the ethernet card's shared memory. Either find the offending card and change its BIOS ROM to be at an address that doesn't conflict, or change the iomem option in the kernel config file so that the card's shared memory is mapped at a non-conflicting address.

ed%d: Invalid irq configuration (%d) must be 2-5 for 3c503. The irq number that was specified in the kernel config file is not valid for the 3Com 3c503 card. The 3c503 can only be assigned to irqs 2 through 5.

ed%d: Cannot find start of RAM.

ed%d: Cannot find any RAM, start : %d, x = %d. The probe of a Gateway card was unsuccessful in configuring the card's packet memory. This likely indicates that the card was improperly recognized as a Gateway or that the card is defective.

ed: packets buffered, but transmitter idle. Indicates a logic problem in the driver. Should never happen.

ed%d: device timeout Indicates that an expected transmitter interrupt didn't occur. Usually caused by an interrupt conflict with another card on the ISA bus.

ed%d: NIC memory corrupt - invalid packet length %d. Indicates that a packet was received with a packet length that was either larger than the maximum size or smaller than the minimum size allowed by the IEEE 802.3 standard. Usually caused by a conflict with another card on the ISA bus, but in some cases may also indicate faulty cabling.

ed%d: remote transmit DMA failed to complete. This indicates that a programmed I/O transfer to an NE1000 or NE2000 style card has failed to properly complete. Usually caused by the ISA bus speed being set too fast.

CAVEATS
Early revision DS8390 chips have problems. They lock up whenever the receive ring-buffer overflows. They occassionally switch the byte order of the length field in the packet ring header (several different causes of this related to an off-by-one byte alignment) - resulting in "NIC memory corrupt - invalid packet length" messages. The card is reset whenever these problems occur, but otherwise there is no problem with recovering from these conditions.

The NIC memory access to 3Com and Novell cards is much slower than it is on WD/SMC cards; it's less than 1MB/second on 8bit boards and less than 2MB/second on the 16bit cards. This can lead to ring-buffer overruns resulting in dropped packets during heavy network traffic.

16bit Compex cards identify themselves as being 8bit. While these cards will work in 8bit mode, much higher performance can be acheived by specifying flags 0x04 (force 16bit mode) in your kernel config file. In addition, you should also specify iosize 16384 to take advantage of the extra 8k of shared memory that 16bit mode provides.

BUGS
The ed driver is a bit too aggressive about resetting the card whenever any bad packets are received. As a result, it may throw out some good packets which have been received but not yet transfered from the card to main memory.

SEE ALSO
arp(4), netintro(4), ifconfig(8)

HISTORY
The ed device driver first appeared in FreeBSD 1.0.

AUTHOR
The ed device driver and this manual page were written by David Greenman.