On Mon, Jan 17, 2011 at 06:39:46PM +0100, Tejun Heo wrote:

On Mon, Jan 17, 2011 at 06:34:33PM +0100, Herbert Poetzl wrote:

quoted

hmm, haven't had the time to dig through the specs yet, but
at least addonics seems to disagree here:

http://www.addonics.com/products/host_controller/tutorial_pm.asp

but maybe that's just a marketing page with no relation
to reality ....

That's hardware RAID PMP.  It would just show up as a single drive to
the host.  They can do whatever they want to if they do that.

okay, understood.

quoted

quoted

AFAIK, it just doesn't care.  It could be ses-2 or whatever else.  It
just transmits the binary blob it receives via sysfs and vice-versa.

the interesting part here is, that the AHCI host controller
my PMP is connected to recognizes the PMP perfectly fine
(i.e. more than one drive works just as expected), but doesn't
seem to allow for the em_message part (despite the fact that
the attached PMP seems to be SEMB/SEP capable) ...

maybe this is just a bug in the kernel code, maybe the AHCI
implementation doesn't allow a PMP to receive enclosure
management messages at all ...

AFAIK, the ahci em message thing is not via PMP. 
It's for cases where the ahci controller is directly connected 
to an enclosure. Well, that's my understanding anyway.

okay, so something similar would be useful for controlling
enclosures attached to PMPs then?

what would be the 'proper' place in the sysfs tree, espceically
as the PMP doesn't show up there (yet)?

how would I go about adding something like that to the kernel
and where should it be placed (sysfs and code wise)?

thanks in advance,
Herbert

-- 
tejun