SSD drive appears to have been "downgraded" from SATA 2 to SATA 1

[Mike Clarke]

On Wed, 9 Nov 2016 22:20:02 +0000
Mike Clarke <jmc-freebsd2 at milibyte.co.uk> wrote:

> Could there be any way that the system could at some time have forced
> the drive down to SATA 1, in which case how do I revert it? Or is it
> more likely that I have a faulty SSD drive?

I've now managed to establish that the drive had been functioning in
SATA 2 300MB/s mode until yesterday when I re-partitioned it to
overcome a problem which had been preventing me from booting from it.
Copies of /var/run/dmesg.boot from my backups show that the drive was
performing as SATA 2 300MB/s until yesterday.

Before re-partitioning the drive I used camcontrol to clear its
contents and mark all cells empty with:

camcontrol security ada0 -s buhbyesweetdata -e buhbyesweetdata

I'm now only seeing SATA2 150MB/s for that drive.

curlew:/home/mike% camcontrol identify ada0 | head -2
pass1: <SanDisk SD6SB2M128G1022I X210400> ATA8-ACS SATA 3.x device
pass1: 150.000MB/s transfers (SATA 1.x, UDMA5, PIO 512bytes)

It looks as though the camcontrol security command has somehow also
caused the drive to drop down to SATA 1 mode. Is there any way I can
use camcontrol (or any other utility) to restore this?

-- 
Mike Clarke