[PATCH] memory: tegra: Remove GPU from DRM IOMMU group

[PATCH] memory: tegra: Remove GPU from DRM IOMMU group

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

Commit 63a613fdb16c ("memory: tegra: Add gr2d and gr3d to DRM IOMMU
group") added the GPU to the DRM IOMMU group, which doesn't make any
sense. This causes problems when Nouveau tries to attach to the SMMU
and causes it to fall back to using the DMA API.

Remove the GPU from the DRM groups to restore the old behaviour. The
GPU should always have its own IOMMU domain to make sure it can map
buffers into contiguous chunks (for big page support) without getting
in the way of mappings from the DRM group.

Fixes: 63a613fdb16c ("memory: tegra: Add gr2d and gr3d to DRM IOMMU group")
Reported-by: Matias Zuniga <matias.nicolas.zc@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/memory/tegra/tegra124.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/memory/tegra/tegra124.c b/drivers/memory/tegra/tegra124.c
index 493b5dc3a4b3..0cede24479bf 100644
--- a/drivers/memory/tegra/tegra124.c
+++ b/drivers/memory/tegra/tegra124.c
@@ -957,7 +957,6 @@ static const struct tegra_smmu_swgroup tegra124_swgroups[] = {
 static const unsigned int tegra124_group_drm[] = {
 	TEGRA_SWGROUP_DC,
 	TEGRA_SWGROUP_DCB,
-	TEGRA_SWGROUP_GPU,
 	TEGRA_SWGROUP_VIC,
 };
 
-- 
2.28.0

Re: [PATCH] memory: tegra: Remove GPU from DRM IOMMU group

[Dmitry Osipenko]

01.09.2020 18:32, Thierry Reding пишет:
> From: Thierry Reding <treding@nvidia.com>
> 
> Commit 63a613fdb16c ("memory: tegra: Add gr2d and gr3d to DRM IOMMU
> group") added the GPU to the DRM IOMMU group, which doesn't make any
> sense. This causes problems when Nouveau tries to attach to the SMMU
> and causes it to fall back to using the DMA API.
> 
> Remove the GPU from the DRM groups to restore the old behaviour. The
> GPU should always have its own IOMMU domain to make sure it can map
> buffers into contiguous chunks (for big page support) without getting
> in the way of mappings from the DRM group.
> 
> Fixes: 63a613fdb16c ("memory: tegra: Add gr2d and gr3d to DRM IOMMU group")
> Reported-by: Matias Zuniga <matias.nicolas.zc@gmail.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/memory/tegra/tegra124.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/memory/tegra/tegra124.c b/drivers/memory/tegra/tegra124.c
> index 493b5dc3a4b3..0cede24479bf 100644
> --- a/drivers/memory/tegra/tegra124.c
> +++ b/drivers/memory/tegra/tegra124.c
> @@ -957,7 +957,6 @@ static const struct tegra_smmu_swgroup tegra124_swgroups[] = {
>  static const unsigned int tegra124_group_drm[] = {
>  	TEGRA_SWGROUP_DC,
>  	TEGRA_SWGROUP_DCB,
> -	TEGRA_SWGROUP_GPU,
>  	TEGRA_SWGROUP_VIC,
>  };
>  
> 

Technically a stable tag is needed for this patch, but I guess the bot
will recognize that this patch is useful for older kernels.

Otherwise looks good!

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>

Re: [PATCH] memory: tegra: Remove GPU from DRM IOMMU group

[Krzysztof Kozlowski]

On Tue, Sep 01, 2020 at 05:32:48PM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> Commit 63a613fdb16c ("memory: tegra: Add gr2d and gr3d to DRM IOMMU
> group") added the GPU to the DRM IOMMU group, which doesn't make any
> sense. This causes problems when Nouveau tries to attach to the SMMU
> and causes it to fall back to using the DMA API.
> 
> Remove the GPU from the DRM groups to restore the old behaviour. The
> GPU should always have its own IOMMU domain to make sure it can map
> buffers into contiguous chunks (for big page support) without getting
> in the way of mappings from the DRM group.
> 
> Fixes: 63a613fdb16c ("memory: tegra: Add gr2d and gr3d to DRM IOMMU group")
> Reported-by: Matias Zuniga <matias.nicolas.zc@gmail.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/memory/tegra/tegra124.c | 1 -

Thanks, applied.

Best regards,
Krzysztof