iMX6Q hangs while entering Suspend state

[selvakumarvelan]

Hi,

We have a iMX6Q customized board running 3.14.28 FSL Linux kernel.  I am trying to put the system in LPM mode. through following steps.

echo enabled > /sys/bus/platform/drivers/imx-uart/2020000.serial/tty/ttymxc0/power/wakeup

echo standby > /sys/power/state

The kernel is compiled with CONFIG_SUSPEND option.

Most of the time the iMX6Q hang in  during disabling not boot CPU and then watchdog reset happens.

[  182.529533] Disabling non-boot CPUs ...

Very rarely iMX6Q enters suspend mode. In this case, wakeup also not happening. Only power recycle is required to bring up the board.

Let me know any addition patch or configuration required for suspend/wakeup for linux kernel 3.14.28

Regards,

Selvakumar V

[igorpadykov]

Hi Selvakumar

what memory LPDDR2 or DDR3 and processor (full marking)

used in the case. Had you run ddr test and rebuild bsp with new ddr settings ?

https://community.freescale.com/docs/DOC-105652

Best regards

igor

-----------------------------------------------------------------------------------------------------------------------

Note: If this post answers your question, please click the Correct Answer button. Thank you!

-----------------------------------------------------------------------------------------------------------------------

[selvakumarvelan]

Hi Igor

Thanks for your reply.

In our custom board we are using LPDDR2 (MT42L128M64D2LL-25 IT_1) and MCIMX6Q6AVT10AD-ND.

We did DDR calibration and stress test through the DDR stress test tool and the stress test is passed.

We configured our LPDDR2 runs in 352MHz.

Reagrds,

Selvakumar V

[igorpadykov]

Hi Selvakumar

highly recommend setting the duty cycle adjustment registers on SDCLK0 and

SDCLK1 to bring the duty cycle as close to 50% as possible. Please set:

MMDC Duty Cycle Control Register (MMDCx_MPDCCR)

0x021B08C0 = 0x24921492

0x021B48C0 = 0x24921492

also please try recommendations provided on

https://community.freescale.com/thread/324903

Best regards

igor

[selvakumarvelan]

Hi Igor,

sorry for late response.

I tried with above mentioned MMDC duty cycle.

MMDC Duty Cycle Control Register (MMDCx_MPDCCR)

0x021B08C0 = 0x24921492

0x021B48C0 = 0x24921492

Still the iMX6Q hangs after enter standby mode.

echo enabled > /sys/bus/platform/drivers/imx-uart/2020000.serial/tty/ttymxc0/power/wakeup

echo standby > /sys/power/state

Regards,

Selvakumar V