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Download User`s Manual Dual Processor System Controller
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Packet Handling Master Operation Slave DataStall CPU WRITE U2S No U2S READ CPU No U2S WRITE CPU Not Supported CPU READ FFB UPA_DATASTALL0 CPU WRITE FFB No U2S READ FFB No U2S WRITE FFB No 5.12 Reserved P_Replys If DSC receives a P_Reply from a slave that is documented in the “UPA Interconnect Architecture” as being “reserved,” then the results will be undefined. 5.13 Error Handling Error handling is detailed in a Error Management section of the UPA Specification, an Error Handling chapter in the Sun-5 System Architecture Specification, and an Error Handling Chapter in the Fusion Desktop System Specification. Here are a list of important points: 1. No software programming error can hang the system. 2. All transactions complete end-to-end. 3. Transactions which are addressed to the slave address space of the same UPA port or directed to ones self in any way have the following effect: a. Reads to ones own slave address space return ambiguous data. b. Writes to ones own address space are dropped silently. c. Interrupts sent to ones self are dropped silently. d. Coherent read of data when it is already in ones own cache is illegal, and is terminated with S_ERR. 5.13.1 Fatal Errors Fatal errors in the DSC can result from the following: February 1997 Dual Processor System Controller ASIC Specification Sun Proprietary 85
