[PATCH] drm/amd/display: Set the domain as GTT when VRAM size <= 32 MB

[Alex Deucher]

On Fri, Aug 27, 2021 at 12:38 AM Mahapatra, Rajib
<Rajib.Mahapatra at amd.com> wrote:
>
> [Public]
>
>
>
> Thanks Alex for your reply.
>
> The patch is not fixing our issue.
>

What exactly is going wrong?  I don't see what this patch fixes.
amdgpu_display_supported_domains() already sets domain to
AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT if the asic can support
display from system memory and the buffer is suitable for display.  If
amdgpu_display_supported_domains() only returns
AMDGPU_GEM_DOMAIN_VRAM, then you shouldn't be adding
AMDGPU_GEM_DOMAIN_GTT because the buffer is not suitable for display
for some reason.  If you force AMDGPU_GEM_DOMAIN_GTT in this case, you
will get hangs on most chips.

Alex

>
>
> Thanks
>
> -Rajib
>
>
>
> From: Deucher, Alexander <Alexander.Deucher at amd.com>
> Sent: Thursday, August 26, 2021 11:48 PM
> To: Mahapatra, Rajib <Rajib.Mahapatra at amd.com>; Wentland, Harry <Harry.Wentland at amd.com>; Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>; Wu, Hersen <hersenxs.wu at amd.com>
> Cc: amd-gfx at lists.freedesktop.org
> Subject: Re: [PATCH] drm/amd/display: Set the domain as GTT when VRAM size <= 32 MB
>
>
>
> [Public]
>
>
>
> I think this may have already been fixed with this patch:
>
> https://gitlab.freedesktop.org/agd5f/linux/-/commit/2a7b9a8437130fd328001f4edfac8eec98dfe298
>
>
>
> Alex
>
>
>
> ________________________________
>
> From: Mahapatra, Rajib <Rajib.Mahapatra at amd.com>
> Sent: Thursday, August 26, 2021 2:07 PM
> To: Wentland, Harry <Harry.Wentland at amd.com>; Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; Wu, Hersen <hersenxs.wu at amd.com>
> Cc: amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>; Mahapatra, Rajib <Rajib.Mahapatra at amd.com>
> Subject: [PATCH] drm/amd/display: Set the domain as GTT when VRAM size <= 32 MB
>
>
>
> [Why]
> In lower carve out (<= 32 MB) devices, it was unable to pin framebuffer in
> VRAM domain for some BO allocations. The device shows below error logs and
> sometimes it reboots too.
>
> amdgpu 0000:02:00.0: amdgpu: 00000000d721431c pin failed
> [drm:dm_plane_helper_prepare_fb] *ERROR* Failed to pin framebuffer with error -12
>
> [How]
> Place the domain as GTT when VRAM size <= 32 MB.
>
> Signed-off-by: Rajib Mahapatra <rajib.mahapatra at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h               |  1 +
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 +++++++++-
>  2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index dc3c6b3a00e5..d719be448eec 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -236,6 +236,7 @@ extern int amdgpu_num_kcq;
>
>  #define AMDGPU_VM_MAX_NUM_CTX                   4096
>  #define AMDGPU_SG_THRESHOLD                     (256*1024*1024)
> +#define AMDGPU_VRAM_MIN_THRESHOLD              (32*1024*1024)
>  #define AMDGPU_DEFAULT_GTT_SIZE_MB              3072ULL /* 3GB by default */
>  #define AMDGPU_WAIT_IDLE_TIMEOUT_IN_MS          3000
>  #define AMDGPU_MAX_USEC_TIMEOUT                 100000  /* 100 ms */
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index e1e57e7465a7..f71391599be1 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -7106,8 +7106,16 @@ static int dm_plane_helper_prepare_fb(struct drm_plane *plane,
>                  return r;
>          }
>
> -       if (plane->type != DRM_PLANE_TYPE_CURSOR)
> +       if (plane->type != DRM_PLANE_TYPE_CURSOR) {
>                  domain = amdgpu_display_supported_domains(adev, rbo->flags);
> +               /*
> +                * Handle devices with lower carve out.
> +                */
> +               if (adev->gmc.real_vram_size <= AMDGPU_VRAM_MIN_THRESHOLD) {
> +                       domain |= (domain & AMDGPU_GEM_DOMAIN_GTT) ? domain :
> +                                  AMDGPU_GEM_DOMAIN_GTT;
> +               }
> +       }
>          else
>                  domain = AMDGPU_GEM_DOMAIN_VRAM;
>
> --
> 2.25.1