imx6q reset error form linux

[1131736298]

The imx6q board designed in this paper will have problems when it is reset after entering the Linux system.but when reset from uboot is ok. when reset from linux,the system will enter uboot,but just show the log is as follows,i can't operate Console

U-Boot 2016.03 (Aug 06 2020 - 14:12:32 +0800)

CPU: Freescale i.MX6Q rev1.5 996 MHz (running at 792 MHz)
CPU: Extended Commercial temperature grade (-20C to 105C) at 44C
Reset cause: POR
Board: MX6-SabreSD
I2C: ready
SPI: ready
DRAM: 2 GiB
PMIC: PFUZE100 ID=0x10
MMC: init usdhc4
FSL_SDHC: 0
SF: Detected M25P80 with page size 256 Bytes, erase size 64 KiB, total 1 MiB

the reset circuit is designed as follows:

How can I solve this problem,can anyone help me?

[weidong_sun]

Hi Andy,

Your reset design is to connect the WDOG signal to the POR_B pin. This connection method has a problem: When the CPU is in the standby or suspend state, the POR_B pin triggers the reset, which may cause the possibility of failing to start.

Because when in standby, the CPU frequency will decrease and the PMIC output voltage will decrease. If POR_B is triggered at this time, startup problems will occur. Because the PMIC output voltage is not enough to make the CPU run.

Therefore, it is recommended that you connect the WDOG signal to the PWRON of the PMIC and use the cold reset method to reset the system.

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

您的reset设计是把WDOG信号接在了POR_B引脚上，这种连接方法存在一个问题：当CPU处于standby或者suspend状态时，POR_B引脚触发reset，会造成无法启动的可能。

因为当standby时，CPU频率会降低，PMIC输出电压会降低，这时候触发POR_B，是会发生启动问题的。因为PMIC输出电压不足以让CPU跑起来。

所以，建议您把WDOG信号接到PMIC的PWRON上，使用cold reset方式复位系统。

您完全可以参考IMX6Q-SDP/B的设计方法。

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

Hope above information is helpful to you.

Have a nice day!
B.R,

Weidong

[1131736298]

Thank you for your answer. I have solved this problem

[Ryze]

Hi,I have same problem in our imx6q-board,could you tell me how did you save the this problem?thank you!