Messages in this thread |  | | From | Evans Jahja <> | | Date | Wed, 26 Nov 2025 03:01:21 +0900 | | Subject | mt8183-kukui: drm/mediatek: dts: Invalid display hw pipeline when probing mediatek-drm |
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Hi,
I have a Lenovo IdeaPad Duet Chromebook CT-X636F, detected as Mediatek krane sku176 board. (mt8183-kukui-krane)
The display failed to initialize on the mainline kernel (linux 6.18-rc7). Using the same config, on stable (linux 6.17.9) the display works fine.
config: https://bugzilla.kernel.org/show_bug.cgi?id=220803
With the system on mainline kernel, I was able to check the serial console, the error on dmesg looks like this:
[ 6.513400] mediatek-drm mediatek-drm.18.auto: Building display pipeline for MMSYS 0 [ 6.514983] mediatek-drm mediatek-drm.18.auto: Display HW Pipeline built with 9 components. [ 6.515009] mediatek-drm mediatek-drm.18.auto: Invalid display hw pipeline. Last component: 38 (ret=-2) [ 6.524422] mediatek-drm mediatek-drm.18.auto: probe with driver mediatek-drm failed with error -22
Temporarily modifying mtk_drm_drv.c by commenting calls to mtk_drm_of_ddp_path_build_one CRTC_EXT and CRTC_THIRD allows the display to function even on mainline. I was also able to add some logging and determine that building the HW pipeline for CRTC_MAIN works, but because building CRTC_EXT fails, the entire display would not initialize.
I am on ArchLinuxARM, its prebuilt kernel was based on linux 6.17.8 with distro-specific patches, also failed to init display. I have not checked why that failed, I am currently focusing on a clean upstream kernel.
Please let me know how I can help. My apologies but I am rather new and may confuse terminologies. I will update as I learn more about the issue.
Best regards,
Evans Jahja
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