[elrepo] No ondemand cpuspeed with 3.18.2-1.el6 kernel

[Robert Nichols]

On 01/14/2015 07:47 PM, Akemi Yagi wrote:
 > On Wed, Jan 14, 2015 at 2:27 PM, Robert Nichols
 > <rnicholsNOSPAM at comcast.net> wrote:
 >> I cannot get CPU ondemand frequency scaling working fully with
 >> kernel-3.18.2-1.el6.elrepo.x86_64.
 >>
 >> /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors shows
 >> only the "performance" and "powersave" governors available, no
 >> "ondemand".
 >>
 >> The driver listed in /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
 >> is "intel_pstate". The script that starts the cpuspeed service does not
 >> recognize that as compatible with "ondemand" and fails to start. I tried
 >> patching the script to add "intel_pstate" to the list of acceptable
 >> drivers. That allows the service to start, but I still have only the
 >> "performance" and "powersave" drivers available.
 >
 > At this point, can you try loading the ondemand module?
 >
 > modprobe cpufreq_ondemand
 >
 > Would this succeed at all?

With my patch, the script does load the cpufreq_ondemand module, and
that succeeds (it shows up in lsmod), but only "performance" and "powersave"
show up in /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors .

On further examination, it seems that the governor is effectively "ondemand"
and it's just the panel applet that isn't reporting correctly.  When I
select "Powersave" the applet shows the CPUs stuck at their minimum
frequency, but if I "grep MHz /proc/cpuinfo" I can see the frequencies
varying between min and max. Also I can run
     echo 1 >/sys/devices/system/cpu/intel_pstate/no_turbo
and limit the freq to 3.5GHz. I can tell by watching the CPU temperature
that it is working.

This is the same as what I see when I run Fedora 20 _IF_ I upgrade to the
latest kernel (3.17.8-200.fc20).  As initially installed (3.11.10 kernel),
Fedora 20 is different, using the acpi_cpufreq module and showing several
governors available ("conservative", "userspace", "powersave", "ondemand",
and "performance").

So, all I am missing is a correct display in the CPU Frequency applet and
the two motherboard temperature sensors that libsensors detects with the
2.6 kernel but somehow can't with the 3.18 kernel. (Not using the acpi
sensors)

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.