Date: Fri, 21 Feb 2014 11:54:15 -0700 From: Ian Lepore <ian@FreeBSD.org> To: freebsd-arm <freebsd-arm@FreeBSD.org> Subject: wandboard / imx6 speed Message-ID: <1393008855.1145.125.camel@revolution.hippie.lan>
next in thread | raw e-mail | index | archive | help
Just a progress update.... Building on the temperature sensor code written recently by Steve Lawrance, I commited changes for imx6 last night that run the processor at full speed as long as the temperature stays below the "throttle point", a configurable temperature that defaults to 10C below the max temp the chip can handle. (I haven't been able to get any of my boards over 55C yet, and the max temp is 95C on solo/dual and 105C on quad.) There are some new sysctls under dev.imx6_anatop.0 to show temperature and frequency. It's not clear that's where they'll always live in the sysctl mibs, other systems use dev.cpu.#. For imx6 these things aren't really per-cpu, there're per-SoC and maybe we need a dev.soc or hw.imx6 or something like that. dev.imx6_anatop.0.cpu_mhz: 984 dev.imx6_anatop.0.temperature: 38.5C dev.imx6_anatop.0.throttle_temperature: 95.0C To change the throttle_temperature, you have to specify a new value in deci-kelvins or add 'C' or 'F' as suffix to the number. The max cpu freq is taken from the OTP data burned into the chip. My wandboard dual doesn't have the right value, it comes up with 792 as the max speed, but the chip markings are the numbers for a 1Ghz part. It appears that Wanboard shipped some units without blowing the right speed fuses. I'm thinking of adding a sysctl/tuneable to override the OTP data to get around it (and to just generally allow for overclocking, because I'm an OC kind of guy at heart). -- Ian
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1393008855.1145.125.camel>