On Monday, July 29, 2013 01:53:32 gregor herrmann wrote: > On Sun, 28 Jul 2013 19:02:20 -0400, Chris Knadle wrote: > > > and the new cpuinfo_cur_freq is root:root 0400 :/ > > > > Concerning root:root 0400 ownership, the workaround I would suggest would > > be to install the 'sysfsutils' package and then to make entries in > > > /etc/sysfs.conf to manually set file mode and ownership, such as: > Oh, nice, I didn't know that.
I didn't either until I tried to use 'cpufreq-set' from the 'cpufrequtils' package as a normal user, and then found that I didn't have permission to manually change the CPU frequency due to the permission/ownership on these files. Normally I use sysfsutils for setting battery charge thresholds with the tp_smapi module, and /etc/sysfs.conf contains comments specific to changing /sys file mode+ownership, so that's how I found out it could do this. > > Another confusing thing is that I'm using Debian's 3.10 kernel, but for > > some reason scaling_cur_freq and cpuinfo_cur_freq both exist on my > > system. (Not sure why that is.) > > It depends on the scaling_driver; I'm using (not by my own decision, > but hey :)) intel_pstate. This makes sense after I read the 'help' in a 'make menuconfig' on the Linux kernel source. > I had a quick look into the kernel sources today, and depending on > the driver's "properties" cpuinfo_cur_freq and/or scaling_cur_freq > are created, at least that was my conclusion. Okay. The output of these two 'files' (pointers to kernel memory) output the same information: # cat cpuinfo_cur_freq scaling_cur_freq 800000 800000 I currently don't know if it's possible to make a [soft|hard]link within /sys, but if that were possible that would be a way around the lack of the scaling_cur_freq filename. If nothing else this should be possible via a custom Linux kernel module. I've experimented with doing this, which is explained in "Linux Device Drivers": https://lwn.net/Kernel/LDD3/ which is another book I'm hoping to get back to reading... P.S. I've subscribed to this bug (manually), so I don't need to be CCed. Cheers -- Chris -- Chris Knadle chris.kna...@coredump.us
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