[PATCH] drm/amdgpu: Fix VRAM BO swap issue

[Alex Deucher]

On Thu, Sep 22, 2022 at 9:19 AM Arunpravin Paneer Selvam
<Arunpravin.PaneerSelvam at amd.com> wrote:
>
> DRM buddy manager allocates the contiguous memory requests in
> a single block or multiple blocks. So for the ttm move operation
> (incase of low vram memory) we should consider all the blocks to
> compute the total memory size which compared with the struct
> ttm_resource num_pages in order to verify that the blocks are
> contiguous for the eviction process.
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>

Please add a Fixes line and any relevant bug report links.

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index b1c455329023..b1223c8e30c9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -426,6 +426,7 @@ static bool amdgpu_mem_visible(struct amdgpu_device *adev,
>  {
>         uint64_t mem_size = (u64)mem->num_pages << PAGE_SHIFT;
>         struct amdgpu_res_cursor cursor;
> +       u64 start, size, total_size = 0;
>
>         if (mem->mem_type == TTM_PL_SYSTEM ||
>             mem->mem_type == TTM_PL_TT)
> @@ -435,8 +436,23 @@ static bool amdgpu_mem_visible(struct amdgpu_device *adev,
>
>         amdgpu_res_first(mem, 0, mem_size, &cursor);
>
> -       /* ttm_resource_ioremap only supports contiguous memory */
> -       if (cursor.size != mem_size)
> +       do {
> +               start = cursor.start;
> +               size = cursor.size;
> +
> +               total_size += size;
> +
> +               amdgpu_res_next(&cursor, cursor.size);
> +
> +               if (!cursor.remaining)
> +                       break;
> +
> +               /* ttm_resource_ioremap only supports contiguous memory */
> +               if (start + size != cursor.start)
> +                       return false;
> +       } while (1);
> +
> +       if (total_size != mem_size)
>                 return false;
>
>         return cursor.start + cursor.size <= adev->gmc.visible_vram_size;
> --
> 2.25.1
>