Ubuntu Manpage: dc — DEC/Intel 21143 and clone 10/100 Ethernet driver

Provided by: freebsd-manpages_12.2-1_all

NAME

       dc — DEC/Intel 21143 and clone 10/100 Ethernet driver

SYNOPSIS

       To compile this driver into the kernel, place the following lines in your kernel configuration file:

             device miibus
             device dc

       Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

             if_dc_load="YES"

DESCRIPTION

The dc driver provides support for several PCI Fast Ethernet adapters and embedded controllers based on
the DEC/Intel 21143 chipset and clones.

All of supported chipsets have the same general register layout, DMA descriptor format and method of
operation. All of the clone chips are based on the 21143 design with various modifications. The 21143
itself has support for 10baseT, BNC, AUI, MII and symbol media attachments, 10 and 100Mbps speeds in full
or half duplex, built in NWAY autonegotiation and wake on LAN. The 21143 also offers several receive
filter programming options including perfect filtering, inverse perfect filtering and hash table
filtering.

Some clone chips duplicate the 21143 fairly closely while others only maintain superficial similarities.
Some support only MII media attachments. Others use different receiver filter programming mechanisms.
At least one supports only chained DMA descriptors (most support both chained descriptors and
contiguously allocated fixed size rings). Some chips (especially the PNIC) also have peculiar bugs. The
dc driver does its best to provide generalized support for all of these chipsets in order to keep special
case code to a minimum.

These chips are used by many vendors which makes it difficult to provide a complete list of all supported
cards.

The dc driver supports the following media types:

autoselect Enable autoselection of the media type and options. The user can manually override the
autoselected mode by adding media options to the /etc/rc.conf file.

Note: the built-in NWAY autonegotiation on the original PNIC 82c168 chip is horribly broken
and is not supported by the dc driver at this time (see the “BUGS” section for details).
The original 82c168 appears on very early revisions of the LinkSys LNE100TX and Matrox
FastNIC.

10baseT/UTP Set 10Mbps operation. The mediaopt option can also be used to enable full-duplex operation.
Not specifying full-duplex implies half-duplex mode.

100baseTX Set 100Mbps (Fast Ethernet) operation. The mediaopt option can also be used to enable
full-duplex operation. Not specifying full-duplex implies half-duplex mode.

The dc driver supports the following media options:

full-duplex Force full duplex operation. The interface will operate in half duplex mode if this media
option is not specified.

Note that the 100baseTX media type may not be available on certain Intel 21143 adapters which support
10Mbps media attachments only. For more information on configuring this device, see ifconfig(8).

HARDWARE

       The dc driver provides support for the following chipsets:

       •   DEC/Intel 21143
       •   ADMtek AL981 Comet, AN985 Centaur, ADM9511 Centaur II and ADM9513 Centaur II
       •   ALi/ULi M5261 and M5263
       •   ASIX Electronics AX88140A and AX88141
       •   Conexant LANfinity RS7112 (miniPCI)
       •   Davicom DM9009, DM9100, DM9102 and DM9102A
       •   Lite-On 82c168 and 82c169 PNIC
       •   Lite-On/Macronix 82c115 PNIC II
       •   Macronix 98713, 98713A, 98715, 98715A, 98715AEC-C, 98725, 98727 and 98732
       •   Xircom X3201 (cardbus only)

       The following NICs are known to work with the dc driver at this time:

       •   3Com OfficeConnect 10/100B (ADMtek AN985 Centaur-P)
       •   Abocom FE2500
       •   Accton EN1217 (98715A)
       •   Accton EN2242 MiniPCI
       •   Adico AE310TX (98715A)
       •   Alfa Inc GFC2204 (ASIX AX88140A)
       •   Built in 10Mbps only Ethernet on Compaq Presario 7900 series desktops (21143, non-MII)
       •   Built in Sun DMFE 10/100 Mbps Ethernet on Sun Netra X1 and Sun Fire V100 (DM9102A, MII)
       •   Built in Ethernet on LinkSys EtherFast 10/100 Instant GigaDrive (DM9102, MII)
       •   CNet Pro110B (ASIX AX88140A)
       •   CNet Pro120A (98715A or 98713A) and CNet Pro120B (98715)
       •   Compex RL100-TX (98713 or 98713A)
       •   D-Link DFE-570TX (21143, MII, quad port)
       •   Digital DE500-BA 10/100 (21143, non-MII)
       •   ELECOM Laneed LD-CBL/TXA (ADMtek AN985)
       •   Hawking CB102 CardBus
       •   IBM EtherJet Cardbus Adapter
       •   Intel PRO/100 Mobile Cardbus (versions that use the X3201 chipset)
       •   Jaton XpressNet (Davicom DM9102)
       •   Kingston KNE100TX (21143, MII)
       •   Kingston KNE110TX (PNIC 82c169)
       •   LinkSys LNE100TX (PNIC 82c168, 82c169)
       •   LinkSys LNE100TX v2.0 (PNIC II 82c115)
       •   LinkSys LNE100TX v4.0/4.1 (ADMtek AN985 Centaur-P)
       •   Matrox FastNIC 10/100 (PNIC 82c168, 82c169)
       •   Melco LGY-PCI-TXL
       •   Microsoft MN-120 10/100 CardBus (ADMTek Centaur-C)
       •   Microsoft MN-130 10/100 PCI (ADMTek Centaur-P)
       •   NDC SOHOware SFA110A (98713A)
       •   NDC SOHOware SFA110A Rev B4 (98715AEC-C)
       •   NetGear FA310-TX Rev. D1, D2 or D3 (PNIC 82c169)
       •   Netgear FA511
       •   PlaneX FNW-3602-T (ADMtek AN985)
       •   SMC EZ Card 10/100 1233A-TX (ADMtek AN985)
       •   SVEC PN102-TX (98713)
       •   Xircom Cardbus Realport
       •   Xircom Cardbus Ethernet 10/100
       •   Xircom Cardbus Ethernet II 10/100

NOTES

       On sparc64 the dc driver respects the local-mac-address? system configuration variable for the  built  in
       Sun  DMFE  10/100  Mbps Ethernet interfaces on Sun Netra X1 and Sun Fire V100.  This system configuration
       variable can be set in the Open Firmware boot monitor using the setenv command or by eeprom(8).   If  set
       to  “false”  (the default), the dc driver will use the system's default MAC address for both of the built
       in devices.  If set to “true”, the unique MAC address of each interface is used rather than the  system's
       default MAC address.

DIAGNOSTICS

dc%d: couldn't map ports/memory A fatal initialization error has occurred.

dc%d: couldn't map interrupt A fatal initialization error has occurred.

dc%d: watchdog timeout A packet was queued for transmission and a transmit command was issued, but the
device failed to acknowledge the transmission before a timeout expired. This can happen if the device is
unable to deliver interrupts for some reason, of if there is a problem with the network connection (cable
or network equipment) that results in a loss of link.

dc%d: no memory for rx list The driver failed to allocate an mbuf for the receiver ring.

dc%d: TX underrun -- increasing TX threshold The device generated a transmit underrun error while
attempting to DMA and transmit a packet. This happens if the host is not able to DMA the packet data
into the NIC's FIFO fast enough. The driver will dynamically increase the transmit start threshold so
that more data must be DMAed into the FIFO before the NIC will start transmitting it onto the wire.

dc%d: TX underrun -- using store and forward mode The device continued to generate transmit underruns
even after all possible transmit start threshold settings had been tried, so the driver programmed the
chip for store and forward mode. In this mode, the NIC will not begin transmission until the entire
packet has been transferred into its FIFO memory.

dc%d: chip is in D3 power state -- setting to D0 This message applies only to adapters which support
power management. Some operating systems place the controller in low power mode when shutting down, and
some PCI BIOSes fail to bring the chip out of this state before configuring it. The controller loses all
of its PCI configuration in the D3 state, so if the BIOS does not set it back to full power mode in time,
it will not be able to configure it correctly. The driver tries to detect this condition and bring the
adapter back to the D0 (full power) state, but this may not be enough to return the driver to a fully
operational condition. If you see this message at boot time and the driver fails to attach the device as
a network interface, you will have to perform a second warm boot to have the device properly configured.

Note that this condition only occurs when warm booting from another operating system. If you power down
your system prior to booting FreeBSD, the card should be configured correctly.

HISTORY

       The dc device driver first appeared in FreeBSD 4.0.

AUTHORS

       The dc driver was written by Bill Paul <wpaul@ee.columbia.edu>.

BUGS

The Macronix application notes claim that in order to put the chips in normal operation, the driver must
write a certain magic number into the CSR16 register. The numbers are documented in the app notes, but
the exact meaning of the bits is not.

The 98713A seems to have a problem with 10Mbps full duplex mode. The transmitter works but the receiver
tends to produce many unexplained errors leading to very poor overall performance. The 98715A does not
exhibit this problem. All other modes on the 98713A seem to work correctly.

The original 82c168 PNIC chip has built in NWAY support which is used on certain early LinkSys LNE100TX
and Matrox FastNIC cards, however it is horribly broken and difficult to use reliably. Consequently,
autonegotiation is not currently supported for this chipset: the driver defaults the NIC to 10baseT half
duplex, and it is up to the operator to manually select a different mode if necessary. (Later cards use
an external MII transceiver to implement NWAY autonegotiation and work correctly.)

The dc driver programs 82c168 and 82c169 PNIC chips to use the store and forward setting for the transmit
start threshold by default. This is to work around problems with some NIC/PCI bus combinations where the
PNIC can transmit corrupt frames when operating at 100Mbps, probably due to PCI DMA burst transfer
errors.

The 82c168 and 82c169 PNIC chips also have a receiver bug that sometimes manifests during periods of
heavy receive and transmit activity, where the chip will improperly DMA received frames to the host. The
chips appear to upload several kilobytes of garbage data along with the received frame data, dirtying
several RX buffers instead of just the expected one. The dc driver detects this condition and will
salvage the frame; however, it incurs a serious performance penalty in the process.

The PNIC chips also sometimes generate a transmit underrun error when the driver attempts to download the
receiver filter setup frame, which can result in the receive filter being incorrectly programmed. The dc
driver will watch for this condition and requeue the setup frame until it is transferred successfully.

The ADMtek AL981 chip (and possibly the AN985 as well) has been observed to sometimes wedge on transmit:
this appears to happen when the driver queues a sequence of frames which cause it to wrap from the end of
the transmit descriptor ring back to the beginning. The dc driver attempts to avoid this condition by
not queuing any frames past the end of the transmit ring during a single invocation of the dc_start()
routine. This workaround has a negligible impact on transmit performance.

Debian October 24, 2011 DC(4)