Re: [PATCH] cpufreq: acpi_cpufreq: base frequency attribute support
From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Date: 2016-02-26 20:23:59
On Fri, 2016-02-26 at 07:27 +0530, Viresh Kumar wrote:
On 25-02-16, 10:07, Srinivas Pandruvada wrote:quoted
If I use cpufreq_driver.attr, then it will create sysfs attribute for every system using acpi-cpufreq, whether they can support it or not. This change is only needed for the later generation of Intel CPUs (IvyBridge and later). There is no standard ACPI way to know the base frequency if we add attribute for all systems using acpi-cpufreq.Why can't you set cpufreq_driver.attr selectively from probe()?
We are setting a cpufreq global variable in cpufreq_driver->attr with this for each cpu. This feature can be absent in certain cpus. So unlike boost it is not system wide, so I have to reset the attr to NULL for some cpus. Can we assume that cpufreq_driver->init(policy) calls are always serialized from cpu online/offline and subsys_interface callback path? Thanks, Srinivas
See below for reference.
commit 21c36d35711d ("cpufreq-dt: make scaling_boost_freqs sysfs attr
available
when boost is enabled")