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DM37x suspend question

Dmitry Bodnya
Expert 1140 points

Other Parts Discussed in Thread: DM3725

Hi!

We have a custom board with DM3725 running PSP04.02.00.07 on it. ES1.2( so OFF mode should be stable on cpu).

Now we have stable suspend/resume sequence, but there some misunderstanding in our board/cpu behaviour.

When I call suspend(echo mem > /sys/power/state) all powerdomains enter target states either I choose RET or OFF mode.

But:

1) I always can wakeup from UART. Can't understand how it could be in OFF mode. Core and Per domains are OFF but I can wakeup from console..

2) Power consumption is the same in RET and OFF state.

3) sys_off_mode pin never goes to active state(mux is correct, polarity is correct, pin reacts on polarity change).

Can someone help me?

Thank you.

  • 0
    TI__Guru 65405 points
    Hi Dmitry,

    The difference between OFF and Retention mode is very thin (Power State Controller saves the flip-flop content only). Therefore you should be ensure whether the system is in RET or OFF state indeed because I expect the consumption to be little bit different. You can read about power domain states in the DM37x TRM section 3.5.7 PRCM Off-Mode Management and 3.5.2.1.5 Power Domain States.

    BR
    Tsvetolin Shulev
  • 0 in reply to Cvetolin Shulev-XID
    Expert 1140 points

    Hi Tsvetolin.

    Thanks for response.

    TRM is like my table-book, especially PRCM chapter. Digging all along.

    I don't know what exactly I made(patches or something else), but now I have sys_offmode pin working. Does it mean that I am reaching OFF mode for 100% or it behaves the same way in RET?

    EDIT. I tested on my board. If I enter 

    echo 0 > /sys/kernel/debug/pm_debug/enable_off_mode

    then after suspend sys_offmode is not active. But with enable_off_mode(==1) it becomes active. So it is OFF mode, I suggest..