topic Re: ipu_cm_read() hangs system in i.MX Processors

ipu_cm_read() hangs system

robertspriggs — Mon, 28 Nov 2016 18:14:57 GMT

We have a custom linux load on a Sabre-based i.MX6 board. We are trying to get video out of the DISP pads and are using the MXC IPUv3 driver. After Linux loads I can not read 0x260_0000 (IPU_CONF) or other registers in that area without the system freezing. I have tried both using devmem from the command line and reading directly from the driver (ipu_common.c in probe()) with the same results.

Our system is built from a custom build tree based on buildroot, and is NOT Android.

Re: ipu_cm_read() hangs system

robertspriggs — Mon, 28 Nov 2016 19:58:41 GMT

I tried removing all IPU and video related drivers from Linux and I still have the same problem with devmem 0x2600000 freezing.

Re: ipu_cm_read() hangs system

igorpadykov — Tue, 29 Nov 2016 07:02:00 GMT

Hi Robert

could you try with memtool from imx-test package

www.nxp.com/lgfiles/NMG/MAD/YOCTO/imx-test-5.4.tar.gz

with nxp linux bsp from

http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-processors/i.mx-6-processors/i.mx6qp/i.mx-6-series-software-and-development-tool-resources:IMX6_SW

Best regards
igor
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Re: ipu_cm_read() hangs system

robertspriggs — Tue, 29 Nov 2016 17:18:53 GMT

Thanks Igor,

However, I found some documentation on device tree configuration of IPU here and tried setting bypass_reset = <1>; Now I can read the registers! Any idea why this would happen?