dmv(4)

Name

dmv − DMV11 communications interface

Syntax

device dmv0 at uba0 csr 0167600 flags 0x???? vector dmvrint dmvxint

Description

The dmv interface provides access to point-to-point communications that runs at speeds from 2.4 Kb/s to 56 Kb/s. DMV11s communicate using the DDCMP link layer protocol.

Several protocols can be multiplexed over a dmv link simultaneously. Conversely, a dmv can be set up so that only one protocol family can use that device. If the latter approach is taken, an SIOCSTATE ioctl must be issued by the protocol family requesting device ownership. The family’s address must appear in the “if_family” structure member, and “if_nomuxhdr” must be set. Before requesting ownership, be sure to disable access to the device for all other protocol families.

The first byte of the flags word can be set up to indicate what mode the device should use. If bit 0 is clear, the device operates in point-to-point DDCMP mode; otherwise, it operates in maintenance mode. If bit 1 is clear, the device operates in full duplex mode; otherwise, it operates in half duplex. If bit 2 is clear, the device operates in dmc compatibility mode; otherwise, it operates using version 4.0 of the DDCMP protocol. The number of outstanding transmit buffers can be increased from a default of 7 to a maximum of 24 buffers by specifying a hexadecimal value in the second byte of the flags word. For example, if flags is set to 0x1800, 24 transmit buffers will be allocated on a device set up to run full duplex in dmc compatibility mode.

Restrictions

Note that maintenance mode should only be used to diagnose data link problems. It is not intended to be used for normal data link traffic.

If specifying maintenance mode, do not set bit 2 of the flags word.

Diagnostics

dmvprobe: can’t start device
The dmv could not be started at boot time.

dmvprobe: device failed diagnostics, octal failure code = %o
The dmv failed diagnostics at boot time.

dmvinit: can’t place dmv%d into internal loopback
Unable to place the dmv into internal loopback requested by user.

dmv%d: done unalloc rbuf
The device returned a receive or transmit buffer that was not allocated to it.

dmv%d: unknown address type %d
An input packet was received that contained a type of address uknown to the driver.

dmv%d bad packet address 0x%x
The device returned a buffer with an unexpected buffer address.

dmv%d: unsolicited information response: ctl = %x, data = %x
The device interrupted the driver with an information response when none was requested.

dmvd%d: bad control %o
A bad parameter was passed to the dmvload routine.

dmv%d: modem disconnect
The modem disconnected, or there was a loss of carrier while a packet was being received.

dmv%d: buffer too small
The remote node sent a packet that was too large to fit in the allocated receive buffer.

dmv%d: receive threshold reported
The dmv reported a receive threshold error.

dmv%d: transmit threshold reached
The dmv reported a transmit threshold error.

dmv%d: select threshold reached
The dmv reported a select threshold error.

dmv%d: babbling tributary reported
The dmv reported a babbling tributary error.

dmv%d: streaming tributary reported
The dmv reported a streaming tributary error.

dmv%d: MOP mode entered while DDCMP was running
dmv%d: MOP mode entered while device was halted
The dmv has entered MOP mode.

dmv%d: non existent memory reported
The dmv accessed non-existent memory.

dmv%d: device queue overflow reported
The dmv reported a queue overflow.

dmv%d: invalid counter pointer
The dmv is reporting the contents of a counter when no request was made to do so.

dmv%d: can’t handle af%d
The dmv was handed a transmit message that has addresses formatted in an unsuitable address family.

dmv%d: internal loopback enable requested
The device is being put in internal loopback at a user’s request.

dmv%d: internal loopback disable requested
The device is being taken out of internal loopback at a user’s request.