dmb(4) Kernel Interfaces Manual dmb(4)
dmb - DMB32 communications multiplexor
device dmb0 at vaxbi? node? flags 0x????
vector dmbsint dmbaint dmblint
A DMB32 device provides eight asynchronous communication lines with modem control. The device driver also supports a connection to a line
printer through the line printer port of the DMB32.
Each line attached to a DMB32 serial line port behaves as described in Input and output for each line may independently be set to run at
any of 16 speeds. See for the encoding.
Bit i of flags can be specified for a to say that a line should be treated as a hardwired connection, with carrier always present. If bit
i of flags is not set, the line operates under full modem control. Modem lines will operate in accordance to the CD (carrier detect), DSR
(data set ready) and CTS (clear to send) leads. Thus, specifying ``flags 0x0004'' in the specification of would cause line 2 on the DMB32
to be treated as hardwired, with carrier always present. In this example, the remainder of the lines will be modem control lines.
The DMB32 provides a synchronous port, but this is not supported by the driver.
dmbinit: async lines unavailable
This message is produced at system boot time, if the DMB32 fails its internal self test, indicating that the asynchronous lines have failed
dmbinit: printer port unavailable
This message is produced at system boot time, if the DMB32 fails its internal self test, indicating that the printer port failed to config-
dmb%d: fifo overflow
The character input fifo overflowed before it could be serviced. This can happen if the CPU is running with elevated priority for too long
a period of time. Overflow errors can indicate that configuration constraints have been reached.
dmb%d: DMA Error. tbuf = 0x%x
A DMA output transfer failed. This can be caused by a memory error or an invalid pte (page table entry). For a description of the error
code in the ``tbuf'' register, see the DMB32 documentation.
dmb%d: DMB Hardware Error. TX.DMA.START failed
The failed to clear the start bit. Normally, this is cleared to signal that a DMA transfer has completed.
dmb%d: Modem Error. tbuf = 0x%x
Indicates a problem with a modem or its cable. For a description of the error code in the ``tbuf'' register, see the DMB32 documentation.
dmb%d: Internal Error. tbuf = 0x%x
Indicates that the DMB32 detected an internal error. For a description of the error code in the ``tbuf'' register, see the DMB32 documen-
hfBdmb%d: uio move error
An error occurred when copying a printer buffer from user space to system space.
The unsupported synchronous port of the DMB32 interrupted because of a problem. Check your interrupt vectors for a conflict with another
(modem lines only)
tty(4), MAKEDEV(8), dmbsp(4)