Re: [PATCH v5 10/11] dt-bindings: display: mediatek: wdma: Add compatibles for more SoCs

[AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>]

On 7/15/26 14:15, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Inconsistent compatibility fallback for 64-bit SoCs (MT8192/MT8195) violating hardware constraints described in the commit.
> --
> 
> --- Patch [10]: [PATCH v5 10/11] dt-bindings: display: mediatek: wdma: Add compatibles for more SoCs ---
> commit ffb6d1b73de2ee2d9fba381dca064a6d8fef7acf
> Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> 
> dt-bindings: display: mediatek: wdma: Add compatibles for more SoCs
> 
> This commit adds missing compatibles for the Write DMA hardware in the
> Display Controller for Dimensity 1200 (MT6893) and Kompanio
> 500/520/820/1200 (MT8183/MT8186/MT8192/MT8195).
> 
>> diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,wdma.yaml b/Documentation/devicetree/bindings/display/mediatek/mediatek,wdma.yaml
>> --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,wdma.yaml
>> +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,wdma.yaml
>> @@ -22,11 +22,16 @@ properties:
>>     compatible:
>>       oneOf:
>>         - enum:
>> +          - mediatek,mt6893-disp-wdma
>>             - mediatek,mt8173-disp-wdma
>>         - items:
>>             - enum:
>>                 - mediatek,mt6795-disp-wdma
>>                 - mediatek,mt8167-disp-wdma
>> +              - mediatek,mt8183-disp-wdma
>> +              - mediatek,mt8186-disp-wdma
>> +              - mediatek,mt8192-disp-wdma
>> +              - mediatek,mt8195-disp-wdma
>>             - const: mediatek,mt8173-disp-wdma
> 
> [Severity: Medium]
> The commit message explicitly excludes MT6893 from falling back to
> MT8173 because it introduces support for destination addresses larger
> than 32 bits. Should this same rule apply to MT8192 and MT8195?
> 
> Since MT8195 (Kompanio 1200) and MT6893 (Dimensity 1200) are the same
> generation of SoCs sharing the same IP, grouping MT8192 and MT8195 here
> implies they can safely fall back to the legacy 32-bit driver.

What?! No!! They're not the same SoC generation, and THAT is also why they
are not compatible with each other?!?!?!?!?!?! :-)))))

Cheers!

> 
> If an OS binds a legacy 32-bit driver to the MT8195 WDMA using this
> fallback, won't it misprogram the DMA addresses by truncating them to 32
> bits when attempting a DMA operation above 4GB?
>