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On 08/20/2011 05:47 PM, Gordan Bobic wrote:
Which kernel are you using?A somewhat older build of Marc's kernel (one month), the one I have in my Debian repository + the change to use 1000 instead of 1200.I presume you mean 1200mV rather than 1200MHz. If it's 1200MHz, I'd like to know where to tweak that. ;)I never said anything of Hz. It's all mV (if it's mV, what are 1.2V used for? The voltage from the battery/charger is clearly 10-12V).Well, my testing has been going on for 6+ hours. Considering I couldn't get an hour without errors before (and sometimes several/hour, and that's just the detected ones), I'd say it's a very definitive improvement. So much so that I'm vaguely tempted to try reducing it to 950mV. ;)Given that the minimum it currently scales to would be 725, 950 is certainly save.Seems there are limits in hardware. I built a kernel with the upper bound set to 900, and now I get a lot of this in the logs, while the CPU is stuck at 216MHz: Failed to set dvfs regulator vdd_cpu Failed to set regulator vdd_cpu for clock cpu to 875mV^^^^^^^^^^^^^^^^ This should have read 975mVcpu-tegra: Failed to set cpu frequency to 1000000kHz over, and over and over. Seems 975mV may be the lower limit, going to try that next.I can confirm that 975mV works without throwing any errors and the CPU does get up to 1GHz. Going to leave it load testing for a few hours and see if it's stable.
And, unfortunately, it isn't stable. It seems that going from 1000mV down to 975mV makes a big difference to stability (multiple errors in the past hour, even worse than at 1200mV).
I still saw one error at 1000mV on my old AC100, but that could have been something else (it is plausible I knocked the USB stick, since there were no errors in the previous 6 hours), so I'm going to re-test and if I can find an error I'll try 1025mV overnight.
Gordan
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