BUG: MTK DRM/HDMI broken on 5.13 (mt7623/bpi-r2)

[Frank Wunderlich <frank-w@public-files.de>]

Hi,

i've noticed that HDMI is broken at least on my board (Bananapi-r2,mt7623) on 5.13.

after some research i noticed that it is working till

commit 2e477391522354e763aa62ee3e281c1ad9e8eb1b
Author: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Date:   Tue Mar 30 13:09:02 2021 +0200

    drm/mediatek: Don't support hdmi connector creation


which is the last of mtk-drm-next-5.13 [1] so i guess a problem with core-patches

dmesg shows the following:

[    7.071342] mediatek-drm mediatek-drm.1.auto: bound 14007000.ovl (ops mtk_dis
p_ovl_component_ops)
[    7.080330] mediatek-drm mediatek-drm.1.auto: bound 14008000.rdma (ops mtk_di
sp_rdma_component_ops)
[    7.089429] mediatek-drm mediatek-drm.1.auto: bound 1400b000.color (ops mtk_d
isp_color_component_ops)
[    7.098689] mediatek-drm mediatek-drm.1.auto: bound 14012000.rdma (ops mtk_di
sp_rdma_component_ops)
[    7.107814] mediatek-drm mediatek-drm.1.auto: bound 14014000.dpi (ops mtk_dpi
_component_ops)
[    7.116338] mediatek-drm mediatek-drm.1.auto: Not creating crtc 1 because com
ponent 9 is disabled or missing
....
[   38.403957] Console: switching to colour frame buffer device 160x64
[   48.516398] [drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
[   48.516422] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:41:cr
tc-0] commit wait timed out
[   58.756384] [drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
[   58.756399] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:
32:HDMI-A-1] commit wait timed out
[   68.996384] [drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
[   68.996399] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:33:p
lane-0] commit wait timed out
[   68.996423] [drm:mtk_drm_crtc_atomic_begin] *ERROR* new event while there is
still a pending event
[   69.106385] ------------[ cut here ]------------
[   69.106392] WARNING: CPU: 2 PID: 7 at drivers/gpu/drm/drm_atomic_helper.c:151
1 drm_atomic_helper_wait_for_vblanks.part.0+0x2a0/0x2a8
[   69.106414] [CRTC:41:crtc-0] vblank wait timed out

so i guess the breaking commit may be this:

$ git logone -S"drm_crtc_commit_wait" -- drivers/gpu/drm/
b99c2c95412c 2021-01-11 drm: Introduce a drm_crtc_commit_wait helper

in drivers/gpu/drm/drm_atomic{,_helper}.c

but i cannot confirm it because my git bisect does strange things (after defining 5.13 as bad and the 2e4773915223 as good, second step is before the good commit till the end, last steps are 5.11...). sorry, i'm still new to bisect.

the fix is targeting to 5.12-rc2, is guess because CK Hu's tree is based on this...but the fix was not included in 5.12-rc2 (only after 5.12.0...got it by merging 5.12.14)

maybe you can help me?

regards Frank

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next-5.13