Apparatus and method for performing a rebalance of resources for one or more devices at boot time

A method for performing a resource rebalance during a boot operation of a computer including a plurality of devices in a device tree, the method comprising:

• receiving at least one signal indicative of a desired set of requested resources from each of the plurality of devices to enable the plurality of devices to operate in an intended manner;
• determining that at least one first child device of the plurality of devices requires more resources than an amount previously assigned thereto;
• locating a lowest common parent device to the at least one first child device, the lowest common parent device and the at least one first child device forming a lowest common subtree;
• determining a resource range corresponding to a first available range of resources that are made available to the lowest common subtree;
• calculating a resource requirement corresponding to a first requested range of resources that includes at least one of a non-relocatable resource request and a relocatable resource request for the lowest common subtree, wherein the non-relocatable resource request corresponds to a resource request for one or more of bus numbers and memory addresses that can only be assigned to a particular device that resides in a particular location within the computer and wherein the relocatable resource request corresponds to a resource request for one or more of bus numbers and memory addresses that can be assigned to any device that resides in one or more different locations within the computer;
• and
• comparing the resource requirement to the resource range to determine if the first available range of resources is adequate to satisfy the first requested range of resources.

An apparatus for performing a resource rebalance during a boot operation of a computer, the apparatus comprising:

• a resource manager comprising a processor and memory for being operably coupled to a plurality of peripheral component interface (PCI) devices in a device tree, the resource manager being configured to:
• receive at least one signal indicative of a desired set of requested resources from each of the plurality of PCI devices to enable the plurality of PCI devices to operate in an intended manner;
• determine that at least one first child device of the plurality of PCI devices requires more resources than an amount previously assigned thereto;
• locate a lowest common parent device to the at least one first child device, the lowest common parent device and the at least one first child device defining a lowest common subtree;
• determine a resource range corresponding to a first available range of resources that are made available to the lowest common subtree;
• calculate a resource requirement corresponding to a first requested range of resources that includes at least one of a non-relocatable resource request and a relocatable resource request for the lowest common subtree;
• compare the resource requirement to the resource range to determine if the first available range of resources is adequate to satisfy the first requested range of resources;
• and
• enable the resource rebalance in the computer such that the at least one first child device is assigned with an adequate amount of resources if the first available range of resources is greater than the first requested range of requested-resources,
• wherein the non-relocatable resource request corresponds to a resource request for one or more of bus numbers and memory addresses that can only be assigned to a particular device that resides in a particular location within the computer and wherein the relocatable resource request corresponds to a resource request for one or more of bus numbers and memory addresses that can be assigned to any device that resides in one or more different locations within the computer.