imx6DualLite bus freq issue

[_angelo_]

Hi,

on a module i have here, with a 1600 ddr3, imx-based kernel 4.9.184 , imx-busfreq driver moves, in certain cases, speed from 24 to 400Mhz, and completely freeze the system.

Is the jump to 400Mhz correct for a ddr3 1600 ( MT41K128M16JT-125) ? 

Was there any known bug in this driver ?

Thanks

Angelo

[igorpadykov]

Hi Angelo

yes 400Mhz is correct. One can try to run ddr test with latest RPA tool and rebuild image with

new calibration coefficients found from ddr test

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX-6-7-DDR-Stress-Test-Tool/ta-p/11082...

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX6ULL-LPDDR2-Script-Aid/ta-p/1121785

try with nxp linux releases :

https://source.codeaurora.org/external/imx/linux-imx/tree/?h=imx_4.9.88_2.0.0_ga

Best regards
igor

[_angelo_]

Hi Igor,

thanks.

I performed calibration and stress test from u-boot by nxp tools.

Running from 327 to 672 Mhz, with or without calibration, stress test reach 620, where i start to get errors.

Also, producer of this sbc is confirm they don't see any issue. So i am still investigating.

Have still one question, in case.

Why stress test gives immediate error if i set a frequency of 24Mhz, and busfreq instead uses 24Mhz as starting idle point ?

Thanks

[igorpadykov]

ddr test supports only dll on mode as described in

Freescale i.MX6 DRAM Port Application Guide-DDR3.pdf

Best regards
igor