influence from the old driver (written by Stefan Grefen) and from
an autochanger driver written by the Systems Programming Group at the
University of Utah Computer Science Department (currently residing
in src/sys/arch/hp300/dev/ac.c).
- split softc size and match/attach out from cfdriver into
a new struct cfattach.
- new "attach" directive for files.*. May specify the name of
the cfattach structure, so that devices may be easily attached
to parents with different autoconfiguration semantics.
- controller calls scsi_done() with error XS_TIMEOUT
- scsi_done() calls sddone()
- sddone() calls disk_unbusy()
- scsi_done() calls controller to retry command (missing the
call to disk_busy())
- controller calls scsi_done()
- scsi_done() calls sddone()
- sddone() calls disk_busy(), which panics because of the imbalance.
Bug noticed by Leo Weppleman, who also suggested this fix; pass an additional
boolean argument ("complete") to the device's "done" routine, with a
value of `0' passed from the previous call to "done", and add an additional
call to "done" when the xfer resources are freed.
- New metrics handling. Metrics are now kept in the new
`struct disk'. Busy time is now stored as a timeval, and
transfer count in bytes.
- Storage for disklabels is now dynamically allocated, so that
the size of the disk structure is not machine-dependent.
- Several new functions for attaching and detaching disks, and
handling metrics calculation.
Old-style instrumentation is still supported in drivers that did it before.
However, old-style instrumentation is being deprecated, and will go away
once the userland utilities are updated for the new framework.
For usage and architectural details, see the forthcoming disk(9) manual
page.
in a 6-byte read/write cdb (namely, length == 0 really means 256), and
that we handle this conservatively by limiting the transfer to 255 blocks.
*sigh* One just never knows how a pre-scsi-1 device is going to behave.
If the read or write request can fit into a 6-byte cdb, then
use a 6-byte cdb, otherwise use the 10-byte as before.
In sd.c:
In sdattach(), make a note if the device is "ancient" (i.e.
inqbuf.version & SID_ANSII == 0).
Implement sdminphys(): if the device is "ancient", shorten the
transfer so it will fit into a 6-byte cdb.
These changes have eliminated the rejected read/write requests on my
Sun 3/60 with 2 ESDI disks behind an Emulex MD21.
