PCN(7D) Devices PCN(7D)

pcn - PCnet Ethernet device driver


The pcn driver is a multi-threaded, loadable, clonable GLDv3-based STREAMS driver supporting the Data Link Provider Interface dlpi(7P) for the AMD PCnet family of Ethernet controllers.

The pcn driver can be used as either a "style 1" or a "style 2" Data Link Service Provider. Physical points of attachment (PPAs) are interpreted as the instance number of the pcn controller as assigned by the operating environment.

The values returned by the driver in the DL_INFO_ACK response are:

Maximum SDU is 1500.
Minimum SDU is 0.
The dlsap address length is 8.
MAC type is DL_ETHER.
SAP length is -2. The 6-byte physical address is immediately followed by a 2-byte SAP.
Service mode is DL_CLDLS.
The broadcast address is the 6-byte Ethernet broadcast address (ff:ff:ff:ff:ff:ff).

The pcn driver performs auto-negotiation to select the link speed and mode. Link speed may be 100Mbps full-duplex, 100Mbps half-duplex, 10Mbps full-duplex, or 10Mbps half-duplex, depending on the hardware adapter type. See the IEEE802.3 standard for more information.

The capabilities advertised by the pcn device can be set using dladm(1m). The driver supports a number of parameters whose names begin with en_ (see below). Each of these parameters contains a boolean value that determines if the device advertises that mode of operations. The adv_autoneg_cap parameter controls whether auto-negotiation is performed. If adv_autoneg_cap is set to 0, the driver forces the mode of operation selected by the first non-zero parameter in priority order as shown below:

                            (highest priority/greatest throughput)
        en_100fdx_cap           100Mbps full duplex
        en_10fdx_cap            10Mbps full duplex
                         (lowest priority/least throughput)

All capabilities default to enabled. Note that changing any capability parameter causes the link to go down while the link partners renegotiate the link speed/duplex using the newly changed capabilities.

See attributes(5) for a description of the following attributes:

Architecture x86
Interface Stability Committed


Special character device.


Device driver (x86)

attributes(5), streamio(7I), dlpi(7p)

IEEE 802.3 — Institute of Electrical and Electronics Engineers, 2002

January 10, 2020