On Jul 16, 2008, at 10:53 AM, Seokmann Ju wrote:
On Jul 15, 2008, at 12:35 PM, james.smart@xxxxxxxxxx wrote:
...
Agreed - for the basic part. However, you're still under the
assumption
that SAS
enumerated everything. Given that some SAS parts could perform
discovery on it's
own, with the LLDD interacting with the transport just enough to
enumerate what it
found useful, this may not always be the case. Additionally, there
aren't a lot
of other "protocols" or "port roles" that exist in SAS - but there
are
in FC.
I see..
There are a couple of more roles have defined in the rports besides
FC_RPORT_ROLE_FCP_TARGET.
The more interesting part is to those things (switch services, non-
FCP
targets)
that the driver did not enumerate. We should allow the directed
enumeration of them
to perform some basic diagnostics or san queries. And once you have
this,
we can really open some interesting doors - why not an app that talks
FICON ? or
something that just message passes between 2 ports ? and so on...
OK.
Overall, I guess that having a device file under the sysfs for the
given port of the HBA should be the approach we need to pursue, then.
And single device file per each port on the instantiated HBA is also
be the case, I think.
For the approach, following are kind of questions that came to me,
1. tte driver has to maintain some sort of table of
the all end ports, and identify one from the table with some index or
opaque data provided by the application for a given FC-CT/ELS pkt.
2. Overall implementation framework should be similar to the one for
SMP in the SAS transport.
I just wanted make sure that I've delivered clear communication.
Please let me know otherwise.
And now, I've got a couple of more questions on the approach.
1. Should the device file created per instantiate HBA, or per port on
the HBA?
I think it should be per port base, for example, when 2-ports HBA
detected, we will create 2 device for the HBA.
2. Should we worry about the 4KB size limit?
I've heard that sysfs attribute has limited size of data it can
transport at one time and that is 4KB.
Thank you,
Seokmann
Thank you,
Seokmann
-- james
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