[PATCH v2 1/3] drm/amdgpu: don't disable ttm buffer funcs on reset

[PATCH v2 1/3] drm/amdgpu: don't disable ttm buffer funcs on reset

[Pierre-Eric Pelloux-Prayer]

Access to hw is already suspended so there are no reasons to
disable ttm buffer funcs.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 6608780ffef2..57e10afb4714 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3167,8 +3167,6 @@ static int amdgpu_device_ip_suspend(struct amdgpu_device *adev)
 		amdgpu_virt_request_full_gpu(adev, false);
 	}
 
-	amdgpu_ttm_disable_buffer_funcs(adev);
-
 	r = amdgpu_device_ip_suspend_phase1(adev);
 	if (r)
 		return r;
-- 
2.43.0

[PATCH v2 2/3] drm/amdgpu: delay ttm buffer func enablement on xgmi

[Pierre-Eric Pelloux-Prayer]

When amdgpu_init_minimal_xgmi is used, SDMA engines init
is delayed so amdgpu_ttm_enable_buffer_funcs must be
called later.

Without this, the check for num_buffer_funcs_scheds will
fail and using ttm buffer funcs later will fail.

---
v2: no need to add a new call. Instead move down the one from
    amdgpu_device_reinit_after_reset after amdgpu_ib_ring_tests
---

Fixes: 3a5da695c8d1 ("drm/amdgpu: only use working sdma schedulers for ttm")
Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 57e10afb4714..53150fe55350 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2479,7 +2479,8 @@ static int amdgpu_device_ip_init(struct amdgpu_device *adev)
 	if (r)
 		goto init_failed;
 
-	amdgpu_ttm_enable_buffer_funcs(adev);
+	if (amdgpu_ip_member_of_hwini(adev, AMD_IP_BLOCK_TYPE_SDMA))
+		amdgpu_ttm_enable_buffer_funcs(adev);
 
 	/* Don't init kfd if whole hive need to be reset during init */
 	if (adev->init_lvl->level != AMDGPU_INIT_LEVEL_MINIMAL_XGMI) {
@@ -5253,8 +5254,6 @@ int amdgpu_device_reinit_after_reset(struct amdgpu_reset_context *reset_context)
 				if (r)
 					goto out;
 
-				amdgpu_ttm_enable_buffer_funcs(tmp_adev);
-
 				r = amdgpu_device_ip_resume_phase3(tmp_adev);
 				if (r)
 					goto out;
@@ -5320,6 +5319,8 @@ int amdgpu_device_reinit_after_reset(struct amdgpu_reset_context *reset_context)
 				r = -EAGAIN;
 				goto end;
 			}
+
+			amdgpu_ttm_enable_buffer_funcs(tmp_adev);
 		}
 
 		if (r)
-- 
2.43.0

[PATCH v2 3/3] drm/amdgpu: remove useless enable/disable of ttm buffer funcs

[Pierre-Eric Pelloux-Prayer]

amdgpu_ttm_disable_buffer_funcs and amdgpu_ttm_enable_buffer_funcs should
each only be called once per amdgpu_device: at startup and teardown.

Therefore the other calls are redundant and can be safely dropped.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 5 -----
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 1 -
 2 files changed, 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 53150fe55350..6abcde8a1a00 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3381,8 +3381,6 @@ static int amdgpu_device_ip_resume(struct amdgpu_device *adev)
 
 	r = amdgpu_device_ip_resume_phase2(adev);
 
-	amdgpu_ttm_enable_buffer_funcs(adev);
-
 	if (r)
 		return r;
 
@@ -4505,8 +4503,6 @@ int amdgpu_device_suspend(struct drm_device *dev, bool notify_clients)
 	if (r)
 		goto unwind_userq;
 
-	amdgpu_ttm_disable_buffer_funcs(adev);
-
 	amdgpu_fence_driver_hw_fini(adev);
 
 	r = amdgpu_device_ip_suspend_phase2(adev);
@@ -4519,7 +4515,6 @@ int amdgpu_device_suspend(struct drm_device *dev, bool notify_clients)
 	return 0;
 
 unwind_evict:
-	amdgpu_ttm_enable_buffer_funcs(adev);
 	amdgpu_fence_driver_hw_init(adev);
 
 unwind_userq:
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 6c6ab4dd6ea9..95f879e723ea 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -2099,7 +2099,6 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
 	}
 
 	/* Change the size here instead of the init above so only lpfn is affected */
-	amdgpu_ttm_disable_buffer_funcs(adev);
 #ifdef CONFIG_64BIT
 #ifdef CONFIG_X86
 	if (adev->gmc.xgmi.connected_to_cpu)
-- 
2.43.0

Re: [PATCH v2 3/3] drm/amdgpu: remove useless enable/disable of ttm buffer funcs

[Alex Deucher]

On Wed, Jun 17, 2026 at 9:39 AM Pierre-Eric Pelloux-Prayer
<pierre-eric.pelloux-prayer@amd.com> wrote:
>
> amdgpu_ttm_disable_buffer_funcs and amdgpu_ttm_enable_buffer_funcs should
> each only be called once per amdgpu_device: at startup and teardown.
>
> Therefore the other calls are redundant and can be safely dropped.

I think there were originally issues where SDMA was attempted to be
used when it was not ready which is why we added all of these cases,
but I think that should be handled properly now.  Series is:
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

>
> Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 5 -----
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 1 -
>  2 files changed, 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 53150fe55350..6abcde8a1a00 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3381,8 +3381,6 @@ static int amdgpu_device_ip_resume(struct amdgpu_device *adev)
>
>         r = amdgpu_device_ip_resume_phase2(adev);
>
> -       amdgpu_ttm_enable_buffer_funcs(adev);
> -
>         if (r)
>                 return r;
>
> @@ -4505,8 +4503,6 @@ int amdgpu_device_suspend(struct drm_device *dev, bool notify_clients)
>         if (r)
>                 goto unwind_userq;
>
> -       amdgpu_ttm_disable_buffer_funcs(adev);
> -
>         amdgpu_fence_driver_hw_fini(adev);
>
>         r = amdgpu_device_ip_suspend_phase2(adev);
> @@ -4519,7 +4515,6 @@ int amdgpu_device_suspend(struct drm_device *dev, bool notify_clients)
>         return 0;
>
>  unwind_evict:
> -       amdgpu_ttm_enable_buffer_funcs(adev);
>         amdgpu_fence_driver_hw_init(adev);
>
>  unwind_userq:
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 6c6ab4dd6ea9..95f879e723ea 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -2099,7 +2099,6 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
>         }
>
>         /* Change the size here instead of the init above so only lpfn is affected */
> -       amdgpu_ttm_disable_buffer_funcs(adev);
>  #ifdef CONFIG_64BIT
>  #ifdef CONFIG_X86
>         if (adev->gmc.xgmi.connected_to_cpu)
> --
> 2.43.0
>