Protocol specific port log page

Bill.Martin at Bill.Martin at
Fri Dec 12 23:19:21 PST 2008

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The Protocol-Specific port log page describes a mechanism for reporting phy
events.  The page is broken up into a list of Protocol-Specific Port log
parameter for SAS.  Each of these parameters includes a 1 byte Parameter
Length field. The parameter is made up of a list of SAS phy log descriptors. 
Each of these SAS phy log descriptors contains 52 bytes of fixed information
and  a number of  phy event descriptors, each of which is 12 bytes long. 
There are at least 27 phy event descriptors which could be applicable to a
SAS device, 4 of which are in the first 52 bytes of the SAS phy log
descriptor.  If all 23 remaining event descriptors are implemented, then the
length of the SAS phy log descriptor for one phy would be 52 + 23 * 12 = 328.
 This exceeds the value that it is possible to put into the Parameter Length
field, and does not even account for the possibility of multiple SAS phy log
descriptors for different phys in the port.
What is the intention for a device which supports more descriptors than the
Protocol-Specific Port log parameter for SAS supports?
Bill Martin
Office of Technology
Industry Standards
916 772-3658
916 765-6875 (Cell)
bill.martin at

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