On 4 July 2013 12:27, Renato Golin <renato.golin@linaro.org> wrote:

On 3 July 2013 18:33, Richard Earnshaw <rearnsha@arm.com> wrote:

keep lowering the clock limit (.../cpufreq/scaling_max_freq) until you get stability. If you don't, then it isn't a heating problem.

It might be a bit too soon, but I just got a few 7h builds out of the boards at 920MHz without a single glitch, whereas before, they wouldn't run for more than 4hs in a row. Both boards are running non-stop since 8pm yesterday.

Yesterday I turned one of the boards back to 1.2GHz (3pm), and it died during the night (2am). The 920MHz is still working. The room temperature didn't go over 26C (the thermometer is by the boards).

I do not believe it is possible to run the 4460 at 1.2GHz on full load without decent thermal management. I can see the frequency changing due to load on my log, so the kernel is doing "something", but I don't think it's actively slowing things down due to temperature concerns.

The heat sink improved the load periods (based on lab data), but as Richard said, thermal conductivity has to be minimum along all the path out, and the plastic casing does not help.

I've run the cpuburn at 920MHz and it runs indefinitely at around 70% max temperature (51C). When I set the maximum to 1.2GHz, it dies in 5 seconds.

Does anyone know how to turn on thermal management on the Linux kernel for the OMAP chips?

cheers,

--renato