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SmartPack / SmartPack-Kernel-Manager

Source code of SmartPack-Kernel Manager, the Ultimate Tool to Manage your Kernel
https://play.google.com/store/apps/details?id=com.smartpack.kernelmanager.pro
GNU General Public License v3.0
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/sys/devices/system/cpu/cpuN/online getting its permissions changed #23

Closed pascua28 closed 5 years ago

pascua28 commented 5 years ago

When changing CPU frequency for per-core policy devices (separate entries for /sys/devices/system/cpu/cpuN/cpufreq), like S5, it also sets /sys/devices/system/cpu/cpuN/online into read-only, breaking userspace hotplugs like mpdecision. Same thing happens when turning off mpdecision, where turning it back on doesn't allow mpdecision to work anymore cause the said sysfs entry is read-only.

sunilpaulmathew commented 5 years ago

Hi You mean changing CPU frequencies? If so, how you change CPU frequencies in a per core basis? Which is beyond the scope of this app. Or do you mean something else? Can you be more specific?

pascua28 commented 5 years ago

Sorry I haven't been clear enough. I didn't mean changing frequencies on a per-core basis. The problem is, when changing frequencies, /sys/devices/system/cpu/cpuN/online gets read only, which breaks mpdecision hot plugging. Need to manually change the permission to get hot plugging back

sunilpaulmathew commented 5 years ago

Thanks for the clarification. I don't know how it happened for you. I never noticed that issue in my old S5 (may be I failed), and current OP5T. Also, by inspecting the respective code (which is taken and nearly unmodified from official KA), I don't find anything changing the permission of "/sys/devices/system/cpu/cpu%d/online". May be a kernel level issue?