PCN(4)							   BSD Kernel Interfaces Manual 						    PCN(4)

NAME

     pcn -- AMD PCnet/PCI Fast Ethernet device driver

SYNOPSIS

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

	   device miibus
	   device pcn

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

	   if_pcn_load="YES"

DESCRIPTION

     The pcn driver provides support for PCI Ethernet adapters and embedded controllers based on the AMD PCnet/FAST, PCnet/FAST+, PCnet/FAST III,
     PCnet/PRO and PCnet/Home Ethernet controller chips.  Supported NIC's include the Allied Telesyn AT-2700 family.

     The PCnet/PCI chips include a 100Mbps Ethernet MAC and support both a serial and MII-compliant transceiver interface.  They use a bus master
     DMA and a scatter/gather descriptor scheme.  The AMD chips provide a mechanism for zero-copy receive, providing good performance in server
     environments.  Receive address filtering is provided using a single perfect filter entry for the station address and a 64-bit multicast hash
     table.

     The pcn 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 rc.conf(5).

     10baseT/UTP  Set 10Mbps operation.  The ifconfig(8) mediaopt option can also be used to select either 'full-duplex' or 'half-duplex' modes.

     100baseTX	  Set 100Mbps (Fast Ethernet) operation.  The ifconfig(8) mediaopt option can also be used to select either 'full-duplex' or
		  'half-duplex' modes.

     The pcn driver supports the following media options:

     full-duplex  Force full duplex operation

     half-duplex  Force half duplex operation.

     For more information on configuring this device, see ifconfig(8).

HARDWARE

     The pcn driver supports adapters and embedded controllers based on the AMD PCnet/FAST, PCnet/FAST+, PCnet/FAST III, PCnet/PRO and PCnet/Home
     Fast Ethernet chips:

     o	 AMD Am79C971 PCnet-FAST
     o	 AMD Am79C972 PCnet-FAST+
     o	 AMD Am79C973/Am79C975 PCnet-FAST III
     o	 AMD Am79C976 PCnet-PRO
     o	 AMD Am79C978 PCnet-Home
     o	 Allied-Telesis LA-PCI

DIAGNOSTICS

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

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

     pcn%d: watchdog timeout  The device has stopped responding to the network, or there is a problem with the network connection (e.g. a cable
     fault).

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

     pcn%d: no memory for tx list  The driver failed to allocate an mbuf for the transmitter ring when allocating a pad buffer or collapsing an
     mbuf chain into a cluster.

     pcn%d: chip is in D3 power state -- setting to D0	This message applies only to adapters which support power management.  Some operating sys-
     tems place the controller in low power mode when shutting down, and some PCI BIOSes fail to bring the chip out of this state before configur-
     ing 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 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.

SEE ALSO

     arp(4), miibus(4), netintro(4), ng_ether(4), ifconfig(8)

     AMD PCnet/FAST, PCnet/FAST+ and PCnet/Home datasheets, http://www.amd.com.

HISTORY

     The pcn device driver first appeared in FreeBSD 4.3.

AUTHORS

     The pcn driver was written by Bill Paul <wpaul@osd.bsdi.com>.

BSD
								 January 31, 2006							       BSD