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

[Daniel Vetter]

On Tue, Jul 06, 2021 at 11:54:39AM +0200, Frank Wunderlich wrote:
> 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 at 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.

drm history runs in parallel with the main tree, so occasionally the
version that's reported as baseline is confusing and older than what you
might expect. Just trust git bisect, it's doing the right thing, and make
sure you test exactly the kernel you're supposed to test. Compiling with
CONFIG_LOCALVERSION_AUTO helps a lot to make sure you're really booting
into the right sha1.

> 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)

Yeah that can also happen because of all the non-linear trees involved in
linux development.

> maybe you can help me?

So now I'm confused, you're talking about a fix, or is it still broken in
latest upstream?
-Daniel

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

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch