On 08/25/2016 03:46 PM, Balbir Singh wrote: > > > On 25/08/16 01:06, Daniel Lezcano wrote: >> On 08/24/2016 04:48 PM, Balbir Singh wrote: >>> >>> >>> On 25/08/16 00:44, Daniel Lezcano wrote: >>>> On 08/19/2016 12:26 AM, Gautham R. Shenoy wrote: >>>>> From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com> >>>>> >>>>> Currently all the idle states registered by a cpu-idle driver are >>>>> enabled by default. This patch adds a mechanism which allows the >>>>> driver to hint if an idle-state should start in a disabled state. The >>>>> cpu-idle core will use this hint to appropriately initialize the >>>>> usage->disable knob of the CPU device idle state. >>>> >>>> Why do you need to do that ? >>>> >>> >>> I think patch 2/2 explains the reason as it uses this infrastructure >> >> Ok, let me elaborate the question, I was not clear. >> >> Why the userspace can't setup the system environment at boot time by >> disabling the state instead of adding extra code to disable it at boot >> time in the kernel and then re-enable it from userspace ? > > Gautham's patches don't want to have those states enabled by default. > They are unlikely to be what production systems need, but likely > what a knowledgeable person can look into selectively enable for > experimentation.
Why not invert the logic ? A knowledgeable person can look into selectively disable for production. In addition, a kernel command line option to specify which state to disable would be appropriate and beneficial for all existing drivers. -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog