System management controller (SMC) negotiation protocol for determining the operational mode of SMCs

Abstract

A computer system module includes a system management controller to negotiate with other system management controllers to determine the controller's initial operational state. In an embodiment, negotiation with other system management controllers is based at least in part on one of controller capability, user configured preferences, module type, and geographical address.

1 . A system comprising: a first system management controller capable of negotiating with at least a second system management controller to determine an initial operational mode of said first system management controller, said first system management controller comprising an input/output port and being capable of sending mode request messages that comply with the Intelligent Platform Management Interface specification via said input/output port to negotiate with said second system management controller to determine said initial operational mode of said first system management controller.  
   
   
       2 . The system of  claim 1 , wherein an available initial operational mode for said first system management controller includes active baseboard management controller mode, standby baseboard management controller mode, and satellite management controller mode.  
   
   
       3 . The system of  claim 1 , wherein said initial operational mode of said first system management controller is based on, at least in part, one of controller mode capability, user configuration preference, module type, and geographical address.  
   
   
       4 . The system of  claim 1 , wherein said initial operational mode of said first system management controller is based on, at least in part, a response, or a lack of response, to said mode request sent via said input/output port.  
   
   
       5 . The system of  claim 1 , comprising a plurality of system management controllers, said first system management controller determining said initial operational mode based on, at least in part, responses, or lack of responses, to said mode request by said plurality of system management controllers.  
   
   
       6 . The system of  claim 1 , wherein the first system management controller further comprises a second input/output port to send a duplicate copy of system management messages to other system management controllers.  
   
   
       7 . A machine-readable medium having stored thereon instructions to be executed by a first system management controller, when executed, said instructions causing the first system management controller to: 
 transition from a reset to a request state; and    send a controller mode request to other system management controllers to determine an initial operational mode of said first system management controller, said controller mode request comprising a message that complies with the Intelligent Platform Management Interface specification.    
   
   
       8 . The machine-readable medium of  claim 7 , wherein said instructions also include instructions to select an initial operational mode based on, at least in part, a received reply, or a lack of a received reply, to said controller mode request from said other system management controllers.  
   
   
       9 . The machine-readable medium of  claim 8 , wherein said instructions include instructions to select an active baseboard mode of operation if no reply to said controller mode request is received.  
   
   
       10 . The machine-readable medium of  claim 8 , wherein said instructions include instructions to select a satellite management controller mode of operation in response to a go to satellite management controller mode reply received from an active baseboard management controller or from a standby baseboard management controller.  
   
   
       11 . The machine-readable medium of  claim 7 , wherein said instructions also include instructions to cause the system management controller to: 
 determine that a mode request has been received from a second system management controller;    send a wait response to the second system management controller if the second system management controller has a lower priority than the first system management controller and the first system management controller is in either a request state or a wait state; and    send a wait response to the second system management controller if the second system management controller has a higher priority than the first system management controller and the first system management controller is in either an active baseboard management controller state or a standby baseboard management controller state.    
   
   
       12 . The machine-readable medium of  claim 11 , wherein the instructions also include instructions to cause the system management controller to: 
 determine the relative priority of the first system management controller and second system management controller based on at least one of controller mode capability, user-configured preference, module type, and geographical address.    
   
   
       13 . The machine-readable medium of  claim 11 , wherein the instructions also include instructions to cause the first system management controller to send one of a wait response and a go to satellite management controller mode to the second system management controller if the second system management controller has an equal or lower priority than the first system management controller and the first system management controller is in either active baseboard management controller state or standby baseboard management controller state.  
   
   
       14 . The machine-readable medium of  claim 11 , wherein the instructions also include instructions to cause the system management controller to: 
 determine that no response should be send to the second system management controller if the second system management controller has a higher priority than the first system management controller and the first system management controller is in either a request state or a wait state; and    determine that no response should be sent to the second system management controller if the first system management controller is in a satellite management controller state.    
   
   
       15 . A method of determining an initial operational mode of a first system management controller comprising: 
 transitioning said first system management controller from a rest state to a request state;    sending a mode request from said first system management controller to at least a second system management controller, said mode request sent as a message that complies with the Intelligent Platform Management Interface specification; and    selecting an initial operational mode of said first system management controller based on, at least in part, a response, or a lack of a response, from said second system management controller to said mode request, said response or lack of response being based on, at least in part, a negotiation protocol state of said second system management controller.    
   
   
       16 . The method of  claim 15 , wherein said response, or lack of response, from said second system management controller is based on, at least in part, the relative priority of said first and second system management controllers.  
   
   
       17 . The method of  claim 16 , wherein said relative priority of said first and second system management controllers is based on at least one of a controller mode capability, a user preference, a controller's module type, or a controller geographical address.  
   
   
       18 . The method of  claim 15 , wherein said initial operation mode of said first system management controller is one of an active baseboard management controller mode, a standby baseboard management controller mode, and a satellite management controller mode.  
   
   
       19 . The method of  claim 18 , wherein an active baseboard management controller mode of operation is selected in the event of a lack of response to the mode request.  
   
   
       20 . The method of  claim 18 , wherein a satellite management controller mode of operation is selected in the event of a go to satellite management controller response to said mode request that is sent by said second system management controller having an active baseboard management controller mode or a standby baseboard management controller mode.