Abstract: Methods and apparatuses for supplying power to processors in multiple processor systems are disclosed. Embodiments comprise a method of monitoring a parameter that is related to a first voltage potential coupled to the processor. When the parameter or condition monitored indicates that the first voltage is bad or faulty, the method generally involves isolating the voltage from the processor, disabling or resetting the processor, and coupling a second voltage potential to the processor. The method may also allow the computer system to continue operating with the processor disabled. Other embodiments comprise an error detection circuit for detecting an error related to a first voltage regulator, a disabling circuit to disable the first voltage regulator in response to the error, a processor isolating circuit, and a voltage switching circuit to supply voltage from a second voltage regulator to the processor.

Abstract: Systems and methods for data intervention for out-of-order castouts are disclosed. Embodiments provide for transmitting snoopable requests received from one or more requesting devices to one or more snoopable devices, which may include requesting devices. Each snoopable device receives snoopable requests and determines if it holds the requested data in modified state. If so then the data is castout and transferred directly to the requesting device without waiting for the data to be read from the slave that was the target of the request. The order of transfers is arbitrated to be consistent with an order of received requests.

Abstract: Methods, and arrangements for extension of clock and data recovery (CDR) loop latency and deactivation of CDR circuits are disclosed. In particular, embodiments address situations in which a receiver, designed to handle spread spectrum clocking, may not always or continuously encounter spread spectrum signals. As a result, power consumption by the receivers may be reduced. Embodiments identify situations in which spread spectrum clocking is unnecessary and may adapt the CDR loop to operate with less power consumption by, e.g., reducing the operating frequency of CDR circuits. For instance, some embodiments employ a flywheel circuit, incorporated into many spread spectrum CDR loops to accelerate adjustments to a sampling clock, to determine when spread spectrum signals are not being encountered. A loop latency controller may then, advantageously, reduce power consumption by reducing frequencies of operation and voltages, and merging or simplifying stages.

Abstract: Methods, and arrangements for power reduction in links, such as transmitters and receivers, based upon global decisions such as the data transmission frequencies, communications media, and traffic types associated with links, are disclosed. In particular, embodiments take advantage of high-level decisions by reconfiguring internal circuits of transmitters and receivers of links to reduce power consumption. At the global level, a decision determines the links that are active, the data frequency at which the links operate, and the media through which the links transmit the data. At the local level, the links receive the decisions and reconfigure circuitry automatically to minimize power based upon the decisions. In some embodiments, the links may receive the decisions in the form of power modes. In further embodiments, the links may receive settings such as on/off settings, data frequency settings, and traffic/media settings, the combination of which indicates power modes.