Re: Marvell 88SE9480 Port Multiplier Support

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Sun, 2017-10-08 at 00:12 -0400, Andrew Ryder wrote:
> Hello,
> 
> Does the mvsas support port multiplier for the marvell 88SE9480 chip?

Not at the present time.  The code to handle SATA port multipliers is
stubbed out in libsas/sas_ata.c

The reason is fairly simple: usually if you're connecting drives via a
SAS host adapter, you want to use SAS expanders because they're way
more featureful and performant than SATA port multipliers, so there's
not much customer pull for support.

> I purchased an Addonics http://addonics.com/products/ad2ms6gpx8-e.php
> but the card fails to see any of the attached drives.
> 
> I found an old message saying it might support sata pmp?
> https://lkml.org/lkml/2014/4/24/413

This patch set was never merged.  There were significant problems with
the EH portion, which Dan Williams reviewed and sent a load of feedback
for but no future patch set incorporating the modifications was ever
forthcoming.

James


> I've attached a dmesg output also and I'm running kernel 4.9.36 if
> that
> helps.
> 
> Andrew