On Thu, May 14, 2015 at 03:06:54PM +0200, Mason wrote: > I added a printk inside twd_update_frequency(). > > http://lxr.free-electrons.com/source/arch/arm/kernel/smp_twd.c?v=3.14#L107 > > I inserted printk("NEW RATE=%lu\n", twd_timer_rate); > right before the call to clockevents_update_freq(). > > When I execute "echo 18500 > scaling_max_freq" > the system is supposed to change the CPU frequency to 18.5 MHz > (I might have a bug lurking there) and PERIPHCLK is 1/2 of that, > i.e 9.25 MHz. > > twd_update_frequency() is called twice: once for each CPU. > (The timers are local to each CPU.) That's expected. I wonder if clockevents_update_freq() is returning an error - which we don't check, and don't print a warning. It would probably be a very good idea to print a warning as a failure to reconfigure the clock events code for a different frequency will lead to this kind of issue. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
