Hi list,

Recently I meet a problem in upstream kernel, which the problem is that
disk driver can not detect FUA/DPO feature of SATA disk.  This machine
has two SATA disks, one is C400-MTFDDAK256M and another is WDC
WD1002FAEX-0, both of them are plugged into mainboard.  I read the data
sheet and both of them support FUA feature.  I am not sure whether this
is a bug or not in kernel.  Meanwhile, I have tested in SAS disk and
kernel displays that the disk supports FUA feature in dmesg.

When we detect FUA feature for SAS disk in kernel, we will use SCSI
command set to detect FUA feature.  Namely, in current kernel, we use
FUA bit to check whether this SAS disk supports FUA feature or not.
However, SATA disk uses ATA command set.  So in current kernel, this
method doesn't detect whether or not SATA disk supports FUA feature.  Am
I missing something?

I put dmesg file in attachment.  Hopefully it is useful.

Regards,
Zheng