[Server-devel] Suggested SATA change by Marvell

[Mitch Bradley]

I don't have enough direct experience with any of the proposed solutions 
to have a preference.


John Watlington wrote:
>
> 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
>
>