[PATCH 3/3] arm64: dts: meson: Describe G12b GPU as coherent

[Neil Armstrong]

Hi Robin,

On 16/09/2020 01:51, Robin Murphy wrote:
> According to a downstream commit I found in the Khadas vendor kernel,
> the GPU on G12b is wired up for ACE-lite, so (now that Panfrost knows
> how to handle this properly) we should describe it as such. Otherwise
> the mismatch leads to all manner of fun with mismatched attributes and
> inadvertently snooping stale data from caches, which would account for
> at least some of the brokenness observed on this platform.
> 
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>
> ---
>  arch/arm64/boot/dts/amlogic/meson-g12b.dtsi | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b.dtsi b/arch/arm64/boot/dts/amlogic/meson-g12b.dtsi
> index 9b8548e5f6e5..ee8fcae9f9f0 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-g12b.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-g12b.dtsi
> @@ -135,3 +135,7 @@ map1 {
>  		};
>  	};
>  };
> +
> +&mali {
> +	dma-coherent;
> +};
> 

Thanks a lot for digging, I'll run a test to confirm it fixes the issue !

Neil