I.MX6DL CPU frequency&SOC_ARM_Voltage configuration

[tommyduan]

       Recently the customer returned three machines, the main problem is that the machine is start for a period of time to restart frequently!Ifind the log that system crash!we use cpu:imx6dl,2GB DDR3,Android 4.4.2,kernel:3.0.35！The system crashed about a minute after startup!At this point, the CPU frequency is reduced by half,I have the following questions:

     (1)Why is the CPU frequency reduced by half after starting up?What causes it?Can I set the unfixed frequency?Where to change?(start cpu frequency is 800HZ   after about a minute is 400HZ;

     (2)When CPU frequency reduce 400HZ，system will restar！At this time, if I change the following ARM voltage from 1.075v to 1.17v, there will be no restart！I checked the official website for 6DL Kernel: 3.0.35. The ARM voltage here is 1.075v！I also tested the voltage correctly！However, I checked the official website and found android 5.1 version with 1.17v Settings！How much is the 6DL Kernel 3.0.35 set here? Is there any parameter data?

     we change the image below!1075000 change 1175000

 I checked the official website and found android 5.1 version with 1.17v Settings！

[igorpadykov]

Hi tommy

for kernel:3.0.35 one can check Chapter 20 CPU Frequency Scaling (CPUFREQ) Driver,

Chapter 18 Low-level Power Management (PM) Driver attached Linux Manual.

And recheck speed grade/operating points for specific part (they may be different for commercial,

industrial, automotive) in Table 8. Operating Ranges Datasheet

i.MX 6DualLite Applications Processors | Dual Arm® Cortex®-A9 @1GHz | NXP 

If increasing ARM voltage helps, this may point to power supplies issues, big ripples (should be <5%),

instability, Check it using guidelines in i.MX6 System Development User’s Guide

https://www.nxp.com/docs/en/user-guide/IMX6DQ6SDLHDG.pdf

Best regards
igor
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[tommyduan]

      Thanks for your replay!I look CPU Frequency Scaling (CPUFREQ) Driver!But I don't understand how to convert CPU mode?I konw first is Performance mode,Later converted to Interactive mode that cpu frequency dynamic change!Where can I set a fixed frequency mode?

[igorpadykov]

from p.159 attached above document: "To change CPU frequency manually,

you can use the userspace CPU frequency governor." p.160 gives example.

Best regards
igor

[tommyduan]

• Can you provide the full name of the file for this information?I find the page number you mentioned does not correspond!

[igorpadykov]

file is in attachment of this thread.