ahci(4) doesn't work with Hitachi 3TB drive

[Dieter BSD]

Testing the 3 TB disk with the 3132 controller went fine.
Smartctl -a  works.  Reading and writing with dd work.
Switched it back to the JMB363 controller.

Smartctl -a does not work.
Still says 150 MB/s rather than 300.

It would be nice if hint.ahcich.1.sata_rev could be set
with a sysctl to avoid the need for a reboot.

Reads smaller than about 90KB appears to always work as expected.
Reads larger than about 90KB sometimes works fine, sometimes are
very slow and give timeout error:

dd if=/dev/ada11 bs=1m count=1 > /dev/null

1048576 bytes transferred in 0.008948 secs (117184368 bytes/sec)
1048576 bytes transferred in 0.008901 secs (117802714 bytes/sec)
1048576 bytes transferred in 0.009025 secs (116184459 bytes/sec)
1048576 bytes transferred in 0.009055 secs (115802062 bytes/sec)
1048576 bytes transferred in 0.008970 secs (116897815 bytes/sec)
1048576 bytes transferred in 0.009054 secs (115814260 bytes/sec)
1048576 bytes transferred in 60.234137 secs (17408 bytes/sec)

ahcich1: Timeout on slot 0
ahcich1: is 00000000 cs 00000000 ss 00000001 rs 00000001 tfd 50 serr 00000000

The larger the read the more likely it is to timeout.

Behaviour is the same with hint.ahcich.1.sata_rev="1"  or ="2"