Message-Id: <1015ADA9-34EA-43E6-A43A-413740C6736E@gmail.com>
Date: Fri, 21 Nov 2025 10:54:59 +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

Thx!

btw: i found that enabling CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER

results with: 
-no anymore boot hang on s4 (with connected hdmi)
-still black screen at s4 boot (with connected hdmi)   
-breaks boot-splash for me on other platforms (allwinner, rockchip)

maybe s4 drm series i'm using is not ready for 6.18 change of fbdev framework to DRM?
    
> 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

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