How to limit the i.mx6q core speed/core number to reduce power consumption

[lonsn]

Hi,

We designed a custom i.mx6q board based on sabresd. The CPU is very hot when playing video. Since the i.mx6q performance is high enough for us now and we only care the high temp stability.  We want to find some way to decrease the cpu power consumption more. The system is Android 5.0 and 3.10 kernel. We already disabled the unused module in dtb file. 

How can I limit the i.mx6q cpu frequency(< 792MHz) ?

Can I decrease the used core numbers to 2 without replacing the chip to dual version?

How can I decrease the GPU performance to decrease the power since we only care video play and have not much requirement for the GPU.

[andrzejdziedzic]

Hi

Based on my tests:

- cores can be disabled as described by Yuri - but it won't reduce the temperature

- reducing CPU frequency to minimum also won't help too much.

[lonsn]

Yes, I have tested the cpu core number decrease, totally no any difference in power consumption.

[Yuri]

Hello,

  Please look at my comments below.

1.

  Please use section 4 (Reducing Power Consumption) of the following

app note.

“i.MX 6Dual/6Quad Power Consumption Measurement”

http://cache.nxp.com/files/32bit/doc/app_note/AN4509.pdf

2.

  Kernel boot parameter “maxcpus” may be used to define maximum

number of processors. Please refer to section 4 (Kernel Boot Parameters)

of “i.MX_Linux_Release_Notes.pdf”

Have a great day,
Yuri

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