pmt: document driver options

docs/pmt/man1.rst

@@ -39,6 +39,42 @@ parameter. It accepts the following values:
 :``json-pretty``: JSON (multiple lines, nicely formatted).
 
 
+Device driver options can be specified as integer numbers (see
+``/usr/include/linux/mtio.h``), or using symbolic names:
+
+:``buffer-writes``: Enable buffered writes
+
+:``async-writes``:  Enable async writes
+
+:``read-ahead``: Use read-ahead for fixed block size
+
+:``debugging``: Enable debugging if compiled into the driver
+
+:``two-fm``:  Write two file marks when closing the file
+
+:``fast-mteom``: Space directly to eod (and lose file number)
+
+:``auto-lock``: Automatically lock/unlock drive door
+
+:``def-writes``: Defaults are meant only for writes
+
+:``can-bsr``: Indicates that the drive can space backwards
+
+:``no-blklims``: Drive does not support read block limits
+
+:``can-partitions``: Drive can handle partitioned tapes
+
+:``scsi2locical``: Seek and tell use SCSI-2 logical block addresses
+
+:``sysv``: Enable the System V semantics
+
+:``nowait``:  Do not wait for rewind, etc. to complete
+
+:``sili``: Enables setting the SILI bit in SCSI commands when reading
+   in variable block mode to enhance performance when reading blocks
+   shorter than the byte count
+
+
 Description
 ===========