i.Mx6 Dual Lite kernel 4.1.41 crashes sometimes during IPU channel disabling at kernel start

[christianfischer]

Hello,

we observe sometimes a problem that our device hangs after a reboot, if the U-Boot 2017.03 starts the kernel 4.1.41.

In this case we only see "Starting kernel ..." at the serial console and our display becomes white with grey stripes.

With different waiting times, we can locate the issue to the four functional calls in the function ipu_disable_channel (drivers/mxc/ipu3/ipu_common.c):

reg = ipu_idmac_read(ipu, IDMAC_CHA_EN(in_dma));
ipu_idmac_write(ipu, reg & ~idma_mask(in_dma), IDMAC_CHA_EN(in_dma));
ipu_cm_write(ipu, idma_mask(in_dma), IPU_CHA_CUR_BUF(ipu->devtype, in_dma));
ipu_cm_write(ipu, tri_cur_buf_mask(in_dma), IPU_CHA_TRIPLE_CUR_BUF(ipu->devtype, in_dma));

The function ipu_disable_channel disables the IPU channels, which ist already activated by the u-boot the show our splash screen.

Unfortunately, it is very difficult to narrow down the issue further.

Has anybody an idea, how we analyze the problem further?

Kind regards

Mark

[igorpadykov]

Hi Mark

unfortunately "kernel 4.1.41" is not officially supported by nxp, sorry.

May be recommended to try official nxp linux, for example uboot imx_v2017.03 & L4.9.11_1.0.0 kernel

from nxp source.codeaurora.org/external/imx/ repository :

https://source.codeaurora.org/external/imx/linux-imx/tree/?h=imx_4.9.11_1.0.0_ga

https://source.codeaurora.org/external/imx/uboot-imx/tree/?h=imx_v2017.03_4.9.11_1.0.0_ga

Documentation

https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applicat...

Issues with non-nxp linux releases may be posted on meta-fsl-arm mailing list:
https://lists.yoctoproject.org/g/meta-freescale

Difference between offical nxp linux and other linux releases is described on

https://community.nxp.com/t5/i-MX-Processors/difference-between-Yocto-Community-BSP-and-Freescale-BS...

>Has anybody an idea, how we analyze the problem further?

as a general suggestion for crash one can try to run ddr test and update 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...

Best regards
igor

[christianfischer]

Hi Igor,

thanks for your feedback.

We have already tested the kernel 4.9.81 and this kernel crashes, too.

During the bring-up we have verified the DDR RAM Timing with the stress tool.

Kind regards

Mark

[igorpadykov]

>The function ipu_disable_channel disables the IPU channels, which ist already

>activated by the u-boot the show our splash screen.

for uboot splash screen one can consider below nxp patches and port it :

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Patch-to-support-uboot-logo-keep-from-ub...

Best regards
igor

[christianfischer · Accepted solution]

Hi Igor,

thanks for the links. We have reviewed the patches and fixed the IPU driver (ipu_common.c function ipu_init_channel) by bypassing the funcation calls:

_ipu_dp_init

_ipu_dc_init

Kind regards

Mark