RE: [PATCH v1 2/2] drm/amdgpu: delay ttm buffer func enablement on xgmi

[Lazar, Lijo]

Public

-----Original Message-----
From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Pierre-Eric Pelloux-Prayer
Sent: Tuesday, June 16, 2026 6:21 PM
To: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Koenig, Christian <Christian.Koenig@xxxxxxx>; David Airlie <airlied@xxxxxxxxx>; Simona Vetter <simona@xxxxxxxx>; Pelloux-Prayer, Pierre-Eric <Pierre-eric.Pelloux-prayer@xxxxxxx>
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: [PATCH v1 2/2] drm/amdgpu: delay ttm buffer func enablement on xgmi

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.

Fixes: 3a5da695c8d1 ("drm/amdgpu: only use working sdma schedulers for ttm")
Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@xxxxxxx>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 3 ++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c   | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 57e10afb4714..2e8954fa5c40 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) { diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
index faac80a8a6eb..c0dca209335e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
@@ -1663,6 +1663,8 @@ static void amdgpu_xgmi_reset_on_init_work(struct work_struct *work)
                if (r && r != -EHWPOISON)
                        dev_err(tmp_adev->dev,
                                "error during bad page data initialization");
+
+               amdgpu_ttm_enable_buffer_funcs(tmp_adev);

<lijo> This gets enabled in the resume path after xgmi reset. It is not needed here.

Thanks,
Lijo

        }
 }

--
2.43.0