On Friday, January 17, 2014 03:42:13 PM Rafael J. Wysocki wrote: > Hi All, > > On some platforms hardware may switch to an energy-saving mode on the fly > on the basis of certain utilization metrics used by it. That usually is > desirable from the energy conservation standpoint, but it generally causes > latencies to increase which may adversely affect some operations. For this > reason, the platforms in question usually provide some interfaces for software > to indicate its latency tolerance and possibly to prevent the energy-saving > modes from being selected too aggressively. > > The following series of patches introduces a device PM QoS type allowing > those interfaces to be used by kernel code and user space. It is designed > in analogy with the existing resume latency device PM QoS type, which allows > some pieces of the existing device PM QoS code to be re-used and makes the > new user space interface fit into the existing framework. > > Patch [1/5] modifies the names of symbols, variables, functions and structure > fields associated with the existing resume latency device PM QoS type to > avoid any confusion with the new one introduced by the subsequent patches. > > Patch [2/5] introduces a new field in struct pm_qos_constraints for specifying > a special value to be returned as the effective requirement when the given list > of PM QoS requirements is empty. That field is necessary for the new latency > tolerance device PM QoS type. > > Patch [3/5] introduces the latency tolerance device PM QoS type along with > documentation. > > Patch [4/5] modifies the ACPI LPSS (Low-Power Subsystem) driver to hook up > LPSS devices to the new latency tolerance device PM QoS interface. > > Patch [5/5] modifies the dev_pm_qos_add_ancestor_request() routine so that it > can be used by drivers of devices without hardware latency tolerance support > for specifying their requirements via the ancestors of those devies. As usual, testing uncovered some issues, so an updated series follows. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
