On 3 July 2013 18:33, Richard Earnshaw rearnsha@arm.com wrote:
On 03/07/13 17:41, Renato Golin wrote:
On 3 July 2013 17:22, Mans Rullgard <mans.rullgard@linaro.org mailto:mans.rullgard@linaro.org> wrote:
I repeat, the 4460 will run at 1.2GHz indefinitely without thermal management.My mistake, I said 1.3GHz when it was actually 1.2GHz. So, at 1.2GHz, it freezes every few hours on full load on both 4430 and 4460.
linaro@linaro-panda-01:~$ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq 1200000
Now what?
keep lowering the clock limit (.../cpufreq/scaling_max_freq) until you get stability. If you don't, then it isn't a heating problem.
Remember that manufacturers match the form of packaging to the expected TDP of the intended usage environment (to keep product costs down). In a mobile part that probably means relatively cheap plastic package because a hot chip would burn a hole in your pocket -- literally. The package almost certainly doesn't have a high thermal conductivity from the chip to the external surface so while a heat sink might help, it won't be as effective as with other packaging options.
Chips expected to dissipate large amounts of power normally have a metal pad on the package so that a heat sink with thermal grease will make a good thermal contact.
The PoP RAM also complicates cooling.