Date: Mon, 20 Feb 2017 21:32:02 +0800 From: Jia-Shiun Li <jiashiun@gmail.com> To: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: Re: patching cpufreq for rpi3 Message-ID: <CAHNYxxPsfJRz_Kp9gPPqmthtP1YabcEGuz8-qac%2B04-u8wyE3A@mail.gmail.com> In-Reply-To: <CAHNYxxOFFeSUQ_8%2BR7RsPn_acoexRNjn%2B51hz6q=GPgz6FYaEg@mail.gmail.com> References: <CAHNYxxOFFeSUQ_8%2BR7RsPn_acoexRNjn%2B51hz6q=GPgz6FYaEg@mail.gmail.com>
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On Wed, Feb 8, 2017 at 3:00 AM, Jia-Shiun Li <jiashiun@gmail.com> wrote: > I was figuring out why frequency scaling does not work > on rpi3, and found that bcm2837 was not caught in some > cases. Thus the attached patch. > > The patch corrects voltage reporting for rpi3. > Frequency scaling still does not work though. > Any ideas? > > So, beginner pitfall #1: bad power https://www.raspberrypi.org/forums/viewtopic.php?t=83372 Make sure you have sufficient power and decent cable. Otherwise power LED will blink or even go off. The little square of rainbow or flash on top right corner of display is also indication of it. BTW you also need heatsink or fan for it to work under load and high frequency without being throttled. One thing that bothers me is on RPi3, hw.cpufreq.turbo defaults not to 0, but -1. And firmware does not limit it to 1/0, but increase/ decrease every time when set repeatedly. So in order to bump speed one actually need to set frequency or turbo twice after booting to make turbo=1. -Jia-Shiun.
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