DDR stress test cause system hang in Linux

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DDR stress test cause system hang in Linux

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Contributor I

Hello NXPs,
Release: Yocto-Sumo (4.14.98_2.0.0_GA)
Board: i.MX8MQ EVK based custom board
We're working on iMX8MQ based custom-designed board with 2GB DDR4 RAM (MCIMX8M-EVK 3GB LPDDR4 RAM) now we're having an issue when doing stress test RAM in linux.
The system always hang when doing RAM stress test with more than 760MB RAM.

Screenshot from 2020-02-26 22-05-56.png

I've already done RAM testing with DDR Tool and mtest in Uboot and all PASSED, then configured the linux system recognized with 2GB RAM.
Does anyone provide the solution for this issue? Any guidance or suggestions will be really helpful.
Best regards,
John.

Updated: Add hang log and DDR Controller Configuration Spreadsheet 

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10 Replies

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NXP TechSupport
NXP TechSupport

Hi John

if " there's no much different between our board and KIT", then

could you try to reproduce issue on nxp reference board

with software described on

i.MX Software and Development Tools | NXP 

Best regards
igor

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291 Views
Contributor I

Hi Igor
My custom board are
CPU: MIMX8MQ6CVAHZAB
RAM: 2GB DDR4 MT40A512M16JY-075E
Uboot: imx_v2018.03_4.14.98_2.0.0_ga
Kernel: imx_4.14.98_2.0.0_ga
My DDR is DDR4 not LPDDR4 so I used MX8M_DDR4_RPA_v9.xlsx then based on that I modified it to match our RAM configuration, you can refer it in the attachement. I followed Chapter 4 in MSCALE_DDR_Tool_User_Guide.pdf to build uboot up and runing, the system can boot to linux and work fined. Then in Linux I used stress command to test memory with 760MB.
I have tested RAM using both DDR Tool and Uboot mtest, it's all show PASS. What I saw is that when application try to allocate or malloc a memory more than 760MB in Linux, it cause the hang issue, for example this command 'stress --vm 1 --vm-bytes 760M'

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NXP TechSupport
NXP TechSupport

Hi John

suggest to try standard linux tool "memtester".

Best regards
igor

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Contributor I

Hi Igor

I used "memtester" and same issue happened, this time with "memtester" the system will hange if input memory bigger than 768MBScreenshot from 2020-03-02 23-32-42.png

Best regards

John

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NXP TechSupport
NXP TechSupport

Hi John

memtester (opposite to ddr tool) also stresses power supplies, so errors using

memtester point to power supplies (ripples, instabilities) issues. May be recommended

to recheck board design using sect.3.6. Power connectivity/routing

i.MX8M Hardware Developer’s Guide

Best regards
igor
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Contributor I

Hi Igor

I double checked with hardware team, then following test cases in Power Consumption Measurement document and comparing to IMX8MQ EVK board, there's no much different between our board and KIT.

Today I built new bl31.bin from without OP-TEE and the Linux system isn't hang anymore.

Is there any idea what might be the root cause?

Best regards

John

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Contributor II

We ran into the same problem and had no idea, did you solve it?

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NXP TechSupport
NXP TechSupport

Hi John

 may be recommended to use latest MX8M_LPDDR4_RPA_v24 tool with test:

i.MX8 MSCALE SERIES DDR Tool Release (V3.10) 

and try attached patch.

Best regards
igor
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Contributor I

Hi Igor

I've tested with new patch and system still hang like before, but this time kernel show some log like bellow

Screenshot from 2020-02-27 21-19-42.png

Any idea?

Best regards.

John

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NXP TechSupport
NXP TechSupport

Hi John

1. what is full processor part number

2. please provide full log: uboot + linux

3. can you confirm that you used latest MX8M_LPDDR4_RPA_v24.xlsx tool

with latest ver.3.10 DDR test version below

i.MX8 MSCALE SERIES DDR Tool Release (V3.10) 

and followed Chapter 4 How to bring up a new MX8MSCALE board

MSCALE_DDR_Tool_User_Guide.pdf included in package
4. please try with uboot and linux from nxp source.codeaurora.org/external/imx/linux-imx  repository
linux-imx - i.MX Linux kernel 

uboot-imx - i.MX U-Boot 

5. what you do mean saying "doing stress test RAM in linux" - is it linux "memtester" or

some custom test ?

Best regards
igor
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