Using kernel 5.4 for Apalis iMX.6

Hello all!

I’m trying to use mainline kernel 5.4 for the Apalis i.MX6 modules placed on our own baseboard. The kernel generally boots fine into a rootfs created via yocto, however there is no framebuffer and therefore no splashscreen and no X11.

As a reference I’ve built the HEAD of branch toradex_5.4.y (commit 941a820dd949) and also this creates not framebuffer. I believe the reason is the kernel message:

[    1.094957] imx-ipuv3 2400000.ipu: failed to reset: -524
[    1.100321] imx-ipuv3: probe of 2400000.ipu failed with error -524
[    1.185446] imx-ipuv3 2800000.ipu: failed to reset: -524
[    1.190792] imx-ipuv3: probe of 2800000.ipu failed with error -524

To rule out my DT I’ve tried to boot with imx6q-apalis-eval.dts. This created additionally errors about the DT but no framebuffer either:

[    1.139447] imx-drm display-subsystem: parent device of /ldb/lvds-channel@0 is not available

I would like to use mainline and a current release to later integrate things from other branches. There is no need for fancy videos etc, X11 is enough. Is my assumption correct that this error 524 (ENOTSUPP) is the reason for the missing framebuffer?

Best regards,

Added logs, .config and DTS

Based on the imx_v6_v7_defconfig one may actually get all four display interfaces going on that kernel. Unaccelerated X11 may be achieved using regular DRM/modesetting.