[PATCH 05/10] video: rockchip: Add VOP2 support

[Chaoyi Chen]

Hi Dang,

On 2025/1/19 21:41, Dang Huynh wrote:
> Hi Andy,
>
> On Sunday, January 19, 2025 9:10:10 AM UTC Andy Yan wrote:
>> Hi Danq,
>>
>> Do you have tests with this u-boot video enabled then boot a linux kernel
>> also with drm display enabled?
>>
> Yes, I booted Linux with U-Boot VOP2 and Linux VOP2 enabled without any
> problem.
The power domain of the VOP is reset during the kernel boot process on 
RK356X, which effectively resets the VOP. If the PD is not reset when 
the VOP is active, it may not be able to reset the IOMMU which cause VOP 
fault. You can verify this by setting PD to always on. In addition, the 
RK3588 may have a similar problem.
>
>> Because the u-boot video been enabled with no-mmu, when it runs into linux
>> kernel with the window/plane you enable at u-boot stage, when linux kernel
>> enable the iommu, there is a moment the window will read the memory through
>> iommu, but the framebuffer you set in u-boot stage has not been mapped by
>> iommu, there is a high probability of causing an IOMMU page fault.
>>
>
>
>