[Server-devel] Suggested SATA change by Marvell

[John Watlington]

All,
    Marvell has been pushing hard for a change in the SATA subsystem.

Currently, this is planned to be:

A.)  A SATA interface on the Discovery 6 (MV-64660), and
a SATA interface on an 88SE6111, connected to the Discovery 6 through  
PCI-E.

The proposal from Marvell is to move to either:

B.)  A Port Multiplier (88SM4140) connected to the SATA interface on  
the Discovery 6,
which supports up to four SATA ports,  or

C.) Two SATA interfaces on an 88SE6121, connected to the Discovery 6  
through PCI-E

The main reason seems to be to move us to a single driver.
Pricing on either of these solutions would be higher (but not in our  
case: Marvell will
sell us any of these three solution for the same price.)
Power will be roughly equivalent, as the PCI-E PHY will always be  
turned on in solutions
A and C, and B requires two SATA hops.

So it comes down to software/driver costs.

Work is being done by Marvell to ensure 88SE61xx family support in  
libata.   The Port Multiplier
isn't well supported by libata at this time.

The SATA interface on the Discovery 6 is very similar to the Hercules  
SATA chipset, currently
supported by the open source mrvlsat driver (?) and is also being  
included in libata (but not
as fast as the 88SE61xx support).

An internal driver for the Discovery 6 SATA, including PM support,  
has been shipping for over
three years.   We will have that code dropped off this afternoon.

Comments ?  Suggestions ?
wad