On 10/20/2017 07:27 PM, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > The special value of 0 for device resume latency PM QoS means > "no restriction", but there are two problems with that. > > First, device resume latency PM QoS requests with 0 as the > value are always put in front of requests with positive > values in the priority lists used internally by the PM QoS > framework, causing 0 to be chosen as an effective constraint > value. However, that 0 is then interpreted as "no restriction" > effectively overriding the other requests with specific > restrictions which is incorrect. > > Second, the users of device resume latency PM QoS have no > way to specify that *any* resume latency at all should be > avoided, which is an artificial limitation in general. > > To address these issues, modify device resume latency PM QoS to > use S32_MAX as the "no constraint" value and 0 as the "no > latency at all" one and rework its users (the cpuidle menu > governor, the genpd QoS governor and the runtime PM framework) > to follow these changes. > > Also add a special "n/a" value to the corresponding user space I/F > to allow user space to indicate that it cannot accept any resume > latencies at all for the given device. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323 > Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > Reported-by: Reinette Chatre <reinette.cha...@intel.com>
Acked-by: Alex Shi <alex....@linaro.org>
