Messages in this thread |  | | From | Evans Jahja <> | | Date | Fri, 28 Nov 2025 11:59:49 +0900 | | Subject | [REGRESSION] mt8183-kukui: dts: changes in dts caused display to no longer initialize - Was: Re: mt8183-kukui: drm/mediatek: dts: Invalid display hw pipeline when probing mediatek-drm |
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#regzbot ^introduced: e72d63fa0563f8a6e98c10fed3a9ce74dc0536e6 #regzbot monitor: https://bugzilla.kernel.org/attachment.cgi?id=308962 Hi,
There has been a regression in the dts for my system mt8183-kukui-krane, where changes in dts/mediatek/mt8183.dtsi broke my machine.
The display works under v6.17.9 but is broken in v6.18-rc7. I was able to replicate / fix the issue just by using the dts from the other version.
> On Wed, Nov 26, 2025 at 3:01 AM Evans Jahja <evansjahja13@gmail.com> wrote: > > > > 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 think this is the issue: https://lkml.org/lkml/2025/9/12/1242
On Wed, Nov 26, 2025 at 2:06 PM Evans Jahja <evansjahja13@gmail.com> wrote: > > Hi Angelo, I was able to isolate the problem further to the dts. After > bisecting the arch/arm64/boot/dts/mediatek/ and building the dts, it > seems like this is the first commit that introduced the issue on my > device. > > commit e72d63fa0563f8a6e98c10fed3a9ce74dc0536e6 (HEAD) > Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> > Date: Thu Jul 24 10:39:08 2025 +0200 > > arm64: dts: mediatek: mt8183: Migrate to display controller OF graph > > I am linking my full bisect log here: > > https://bugzilla.kernel.org/attachment.cgi?id=308962&action=edit
where we're unconditionally adding mmsys_ep_ext.
The issue seems to be caused by the recent addition of CRTC_EXT on the base mt8183
Please kindly take a look. Apologies for any mistake, this is my first issue.
Evans Jahja
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