i.MX6ULL power modes to Linux mapping

[chadwolter]

I am looking for information on how the power modes referenced in the i.MX6ULL datasheet and processor reference manual map to the power modes available in Linux under /sys/power/state.  The state file has 3 settings:

-mem

-standby

-freeze

from chapter 21 of the i.MX_Linux_Reference_Manual, I see that mem appears to map to a state called DORMANT and standby appears to map to a state called STOP, but I am unsure of how these values map back to what is referenced in section 4.1.6 of the datasheet.  Also, what does the 'freeze' parameter map to?  Please provide some clarification or an application note to help answer the question.

PLEASE be advised, I have already reviewed the following documents in an effort to understand this:

1. AN5345 "i.MX6ULL Power Consumption Application Note"

2. i.MX_Linux_Reference_Manual.pdf

3. IMX6ULLIEC.pdf 

4. IMX6ULLRM.pdf

thanks and kind regards

Chad Wolter

[igorpadykov]

Hi Chad

please check Chapter 21 Low-level Power Management (PM) Driver

attached Linux Manual, Table 10-1. Low Power Mode Definition

i.MX6UL Reference Manual

http://www.nxp.com/docs/en/reference-manual/IMX6ULLRM.pdf 

'freeze' is not described in documentation, so this was not tested

and may be considered as "not supported" by software.

DORMANT maps to SNVS section 4.1.6.

Best regards
igor
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[chadwolter]

Ok. Please tell me then how to enact the modes listed in table 10-1 in the i.MX6ULL processor Reference Manual from within Linux. Please provide the actual commands that would need to be entered into the Linux CLI for the following modes:

System IDLE

Low Power IDLE

SUSPEND

[igorpadykov]

Hi Chad

not all power modes are implemented in linux.

Chapter 21 Low-level Power Management (PM) Driver attached Linux Manual

shows what modes are implemeneted. You will have to add support for other low power

modes himself.

Best regards
igor

[chadwolter]

Igor –

Respectfully, I do not believe you are reading what I am writing. I have read chapter 21 in the Linux Manual, and I told you that in the first question I posted to the board. What I am looking to do, again, is to (in Linux) enact the following power modes (from Table 10-1, Page 358, section 10.4.1.7 “System domains layout” in IMX6ULLRM.pdf – rev 0 09/2016). The 3 modes listed in that table are as follows:

1. System Idle

2. Low Power Idle

3. SUSPEND

Now, if I go to chapter 21 of the i.MX_Linux_Reference_Manual.pdf (Document Number: IMXLXRM Rev. 0, 03.2016), the modes listed are as follows (please refer to table 21-1):

1. RUN

2. WAIT

3. STOP

4. DORMANT

If you read further in section 21.1.1, the text there states that the modes in table 21-1 map to the Linux Kernel power management states in the following manner:

1. Standby -> STOP

2. Mem -> DORMANT

3. System idle -> WAIT (*****PLEASE NOTE – this is incorrect as the Linux kernel power management driver DOES NOT take a state of System idle)

With the information I have just presented, PLEASE tell me how the states in chapter 21 of the Linux Reference manual map to the states in table 10-1 in the datasheet. If you cannot answer, I understand…please then direct me to someone who can. I need to get this figured out so I can move on with my design. Any assistance you can provide ASAP would be greatly appreciated.

Kind regards

Chad Wolter

[igorpadykov]

Hi Chad

one can look on AN5345 6ULL Power Consumption Application Note,
check 6.2.3. System Idle mode: system setup - it corresponds to linux
"System idle". Linux Mem (suspend to RAM) maps to SUSPEND in Table 10-1.
https://www.nxp.com/docs/en/application-note/AN5345.pdf

Best regards
igor