siis(4) questions

[Dieter]

The siis(4) man page promises a ada(4) man page, but
I can't find it.  Even tried the online man page tool.

dmesg says:

    ada0 at siisch0 bus 0 target 0 lun 0
    ada0: <Hitachi HDT721010SLA360 ST6OA31B> ATA/ATAPI-8 SATA 2.x device
    ada0: 300.000MB/s transfers
    ada0: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
    ada0: Native Command Queueing enabled

but camcontrol says:

    # camcontrol inquiry ada0 -R
    150.000MB/s transfers

    # camcontrol identify ada0
    [ ... ]
    Feature                      Support  Enable    Value           Vendor
    write cache                    yes      no
    read ahead                     yes      yes
    Native Command Queuing (NCQ)   yes              31/0x1F

So camcontrol disagrees with dmesg about the transfer speed.
And camcontrol doesn't even fill in whether NCQ is enabled or not.

The readcap and modepage stuff doesn't work at all:

    # camcontrol readcap ada0
    (pass0:siisch0:0:0:0): READ CAPACITY(10). CDB: 25 0 0 0 0 0 0 0 0 0
    (pass0:siisch0:0:0:0): CAM Status: SCSI Status Error
    (pass0:siisch0:0:0:0): SCSI Status: Check Condition

    # camcontrol modepage ada0 -l
    camcontrol: error sending mode sense command
    # camcontrol modepage ada0 -m 0
    camcontrol: error sending mode sense command
    # camcontrol modepage ada0 -m 1
    camcontrol: error sending mode sense command
    # camcontrol modepage ada0 -m 2
    camcontrol: error sending mode sense command
    # camcontrol modepage ada1 -m 2
    camcontrol: error sending mode sense command

I get the same problems with Seagate disks, so it isn't just Hitachi.

I suspect that the dmesg info is correct.  I'm not sure whether to
believe *any* of the stuff camcontrol prints out?  Like whether
the write cache is on or not.  And with the modepage stuff not
working, how do I turn the write cache on and off?