Message-Id: <9BCB2E8F-F8FA-4CA4-9039-FADE0D875404@gmail.com>
Date: Fri, 5 Dec 2025 11:03:44 +0100
From: Piotr Oniszczuk <piotr.oniszczuk@...il.com>
To: Ao Xu <ao.xu@...ogic.com>
Cc: Chuan Liu <chuan.liu@...ogic.com>,
 Neil Armstrong <neil.armstrong@...aro.org>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>,
 Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>,
 Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>,
 Kevin Hilman <khilman@...libre.com>,
 Jerome Brunet <jbrunet@...libre.com>,
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
 dri-devel@...ts.freedesktop.org,
 linux-amlogic@...ts.infradead.org,
 devicetree@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/11] dt-bindings: display: meson-dw-hdmi: Add compatible
 for S4 HDMI controller

Ao,

Thx!

Indeed patch helps with boot freeze.
I started to see on monitor - with correct resolution - 4 tuxes in upper left corner :-)

Now i'm getting user space oops like this: 

https://gist.github.com/warpme/b8b757bc1444be8a137849301698ee4b

i'm pretty sure it is related to lack of (or issue with) console at kernel early init in user space.

As kernel with s4 hdmi code works for you - but traps for me - i think there is still issue with s4 hdmi code.
I suspect it is because diff between: my kernel config and yours.
(so it is exposing existing hidden issue)

btw: I'm not surprised by this as my kernel config is multi-soc (common for bcm25xx/27xx/s905/s912/g12/sm1/s4/h6/h616/a523/h700/rk33xx/rk35xx/qcs6490)
Usually kernel configs done for single soc (probably config you are using to test s4 hdmi code) are not exposing hidden issues exposed by multi-soc config (like mine config). 
I deal with such issues multiple times in past.

multi-soc config i'm using is like this: https://github.com/warpme/minimyth2/blob/master/script/kernel/linux-6.18/files/linux-6.18-arm64-armv8.config

May you pls try to compile your s4 hdmi code with above config?
I'm quite sure it will expose to you issue i'm getting....




> Wiadomość napisana przez Ao Xu <ao.xu@...ogic.com> w dniu 5 gru 2025, o godz. 08:09:
> 
> Hi Piotr，
> 
>     I applied this patch: https://github.com/warpme/minimyth2/blob/master/script/kernel/linux-6.18/files/0312-drm-meson-add-vpu-clk-setting-for-S4.patch, and ran it on the board.
> 
>     I encountered the same issue—the system froze.
> 
>     I found that the patch has a few minor problems. After fixing them, the system runs normally. Could you try the following patch?
> 
> 
> 在 2025/12/3 13:56, Ao Xu 写道:
>> Hi Piotr，
>> 
>>     I will need about two more days to look into it. I will follow up with you ASAP.
>> 
>> 
>> 在 2025/12/2 16:29, Piotr Oniszczuk 写道:
>>> [You don't often get email from piotr.oniszczuk@...il.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>> 
>>> [ EXTERNAL EMAIL ]
>>> 
>>> Ao,
>>> Any chance for updated s4 hdmi series for 6.18?
>>> 
>>> 
>>>> Wiadomość napisana przez Ao Xu <ao.xu@...ogic.com> w dniu 21 lis 2025, o godz. 03:55:
>>>> 
>>>> Hi Piotr，
>>>> 
>>>>      I will check this issue
>>>> 
>>>> 在 2025/11/19 18:27, Piotr Oniszczuk 写道:
>>>>> [You don't often get email from piotr.oniszczuk@...il.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>>>> 
>>>>> [ EXTERNAL EMAIL ]
>>>>> 
>>>>> Pls see inline
>>>>> 
>>>>>> Wiadomość napisana przez Chuan Liu <chuan.liu@...ogic.com> w dniu 19 lis 2025, o godz. 03:57:
>>>>>> 
>>>>>> Hi Piotr,
>>>>>> 
>>>>>> 
>>>>>> On 11/18/2025 10:50 PM, Piotr Oniszczuk wrote:
>>>>>>> [You don't often get email from piotr.oniszczuk@...il.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>>>>>> [ EXTERNAL EMAIL ]
>>>>>>> Ao,
>>>>>>> Is there any chance to get this s4 drm hdmi series for current 6.18?
>>>>>>> (i tried backport this series to 6.18 but have some issues with reparent vpu_0_sel to sysclk_b_sel)
>>>>>> Why do we need to reparent vpu_0_sel to sysclk_b_sel? is there any
>>>>>> background here?
>>>>> Well - it looks it is because bug....
>>>>> Martin Blumenstingl had perfect eye and catch typo in patch https://lore.kernel.org/all/20250110-drm-s4-v1-11-cbc2d5edaae8@amlogic.com/: 
>>>>> 
>>>>> By replacing:
>>>>> assigned-clock-parents = <&clkc_periphs CLKID_FCLK_DIV3>,
>>>>> <0>, /* Do Nothing */
>>>>> <&clkc_periphs CLKID_VPU_0>,
>>>>> <&clkc_periphs CLKID_FCLK_DIV4>,
>>>>> <0>, /* Do Nothing */
>>>>> <&clkc_periphs CLKID_VAPB_0>;
>>>>> 
>>>>> with:
>>>>> assigned-clock-parents = <&clkc_pll CLKID_FCLK_DIV3>,
>>>>> <0>, /* Do Nothing */
>>>>> <&clkc_periphs CLKID_VPU_0>,
>>>>> <&clkc_pll CLKID_FCLK_DIV4>,
>>>>> <0>, /* Do Nothing */
>>>>> <&clkc_periphs CLKID_VAPB_0>;
>>>>> 
>>>>> dmesg is like this https://termbin.com/6020
>>>>> 
>>>>> So i'm getting hdmi working - but only when device boots _without_ connected hdmi at boot (and connected later)
>>>>> If hdmi is connected at boot - boot hangs at:
>>>>> 
>>>>>      0.341676] meson-dw-hdmi fe300000.hdmi-tx: Detected HDMI TX controller v2.01a with HDCP (meson_dw_hdmi_phy)
>>>>> [    0.342750] meson-dw-hdmi fe300000.hdmi-tx: registered DesignWare HDMI I2C bus driver
>>>>> [    0.343660] meson-drm ff000000.vpu: bound fe300000.hdmi-tx (ops meson_dw_hdmi_ops)
>>>>> [    0.344832] [drm] Initialized meson 1.0.0 for ff000000.vpu on minor 0
>>>>> 
>>>>> FYI: It is after applying https://patchwork.kernel.org/project/linux-amlogic/cover/20250110-drm-s4-v1-0-cbc2d5edaae8@amlogic.com/ on mainline 6.18 (with some my adjustments on this series required by changes in 6.18).
>>>>> For VPU clk changes see https://github.com/warpme/minimyth2/blob/master/script/kernel/linux-6.18/files/0312-drm-meson-add-vpu-clk-setting-for-S4.patch
>>>>> It is 6.18 adaptation of https://patchwork.kernel.org/project/linux-amlogic/patch/20250110-drm-s4-v1-9-cbc2d5edaae8@amlogic.com/
>>>>> 
>>>>> As kernel hangs - i have limited caps to drill where root cause is.
>>>>> 
>>>>> Maybe above hang is reason of my backports or missing any pre-req required to get s4 drm working?
>>>>> Anyway - it will be good to test with updated to 6.18 series of Add DRM support for Amlogic S4 (plus info about any pre-req required to get s4 drm working)
>>>>> 
>>>>> 
>>>>>> The vpu_clk on S4 doesn't support sysclk_b_sel as one of its
>>>>>> selectable clock sources, so this reparent operation will definitely
>>>>>> fail. This has nothing to do with the kernel version.
>>>>>> 
>>>>>>>> Wiadomość napisana przez Ao Xu via B4 Relay <devnull+ao.xu.amlogic.com@...nel.org> w dniu 10 sty 2025, o godz. 06:39:
>>>>>>>> 
>>>>>>>> From: Ao Xu <ao.xu@...ogic.com>
>>>>>>>> 
>>>>>>>> Add devicetree document for S4 HDMI controller
>>>>>>>> 
>>>>>>>> Signed-off-by: Ao Xu <ao.xu@...ogic.com>
>>>>>>>> ---
>>>>>>>> Documentation/devicetree/bindings/display/amlogic,meson-dw-hdmi.yaml | 1 +
>>>>>>>> 1 file changed, 1 insertion(+)
>>>>>>>> 
>>>>>>>> diff --git a/Documentation/devicetree/bindings/display/amlogic,meson-dw-hdmi.yaml b/Documentation/devicetree/bindings/display/amlogic,meson-dw-hdmi.yaml 
>>>>>>>> index 84d68b8cfccc86fd87a6a0fd2b70af12e51eb8a4..6e0a8369eee915fab55af24d450a6c40e08def38 100644
>>>>>>>> --- a/Documentation/devicetree/bindings/display/amlogic,meson-dw-hdmi.yaml 
>>>>>>>> +++ b/Documentation/devicetree/bindings/display/amlogic,meson-dw-hdmi.yaml 
>>>>>>>> @@ -55,6 +55,7 @@ properties:
>>>>>>>>            - const: amlogic,meson-gx-dw-hdmi
>>>>>>>>        - enum:
>>>>>>>>            - amlogic,meson-g12a-dw-hdmi # G12A (S905X2, S905Y2, S905D2)
>>>>>>>> +          - amlogic,meson-s4-dw-hdmi # S4 (S905Y4)
>>>>>>>> 
>>>>>>>>    reg:
>>>>>>>>      maxItems: 1
>>>>>>>> 
>>>>>>>> -- 
>>>>>>>> 2.43.0
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> _______________________________________________
>>>>>>>> linux-amlogic mailing list
>>>>>>>> linux-amlogic@...ts.infradead.org
>>>>>>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>>>>> _______________________________________________
>>>>>>> linux-amlogic mailing list
>>>>>>> linux-amlogic@...ts.infradead.org
>>>>>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> <fix-vpu-clk-setting-for-s4.patch>

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