Re: exynos-mixer 14450000.mixer: [drm:exynos_drm_register_dma] *ERROR* Device 14450000.mixer lacks support for IOMMU

[Mario Marietto <marietto2008@xxxxxxxxx>]

@Marek Marczykowski-Górecki : I've recompiled the kernel 6.6 on my ARM Chromebook to test if your patch helped to fix the "black screen" issue. And not,it does not work. Is this expected or is there something wrong with your patch ?

On Thu, Nov 2, 2023 at 11:00 AM Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote:

On 01.11.2023 03:50, Chuck Zmudzinski wrote:

On 10/31/2023 7:45 PM, Stefano Stabellini wrote:

Unfortunately there is no easy solution.

Do you know the version of the SMMU available on the platform? 

I am trying to discern, but I doubt we have v3 because we are
working on a very old chromebook from 2012, and I am finding
patches for smmv3 in Linux not starting until 2015. It is good to
know about this option, though, for future work we might do on newer
devices.

Just to clarify. Exynos SMMU is a custom hardware designed by Samsung, it is not based on ARM's SMMU. Linux has a separate driver for it.

> ...

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

 

--

Mario.