Because too many things are involved in this workaround, we need more comments to avoid pitfalls.
Change-Id: I5d7917296dd5f5edb45921118cf8e7d778d40de1 Signed-off-by: Yong Zhao <[email protected]> --- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 5 ++++- .../gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 18 +++++++++++++++--- 2 files changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 1947a326de57..10f6f4b21b44 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -1041,7 +1041,10 @@ int amdgpu_ttm_gart_bind(struct amdgpu_device *adev, if (r) goto gart_bind_fail; - /* Patch mtype of the second part BO */ + /* The memory type of the first page defaults to UC. Now + * modify the memory type to NC from the second page of + * the BO onward. + */ flags &= ~AMDGPU_PTE_MTYPE_VG10_MASK; flags |= AMDGPU_PTE_MTYPE_VG10(AMDGPU_MTYPE_NC); diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c index 436b7f518979..5b11190ff6e6 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c @@ -87,9 +87,21 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd, int retval; struct kfd_mem_obj *mqd_mem_obj = NULL; - /* From V9, for CWSR, the control stack is located on the next page - * boundary after the mqd, we will use the gtt allocation function - * instead of sub-allocation function. + /* For V9 only, due to a HW bug, the control stack of a user mode + * compute queue needs to be allocated just behind the page boundary + * of its regular MQD buffer. So we allocate an enlarged MQD buffer: + * the first page of the buffer serves as the regular MQD buffer + * purpose and the remaining is for control stack. Although the two + * parts are in the same buffer object, they need different memory + * types: MQD part needs UC (uncached) as usual, while control stack + * needs NC (non coherent), which is different from the UC type which + * is used when control stack is allocated in user space. + * + * Because of all those, we use the gtt allocation function instead + * of sub-allocation function for this enlarged MQD buffer. Moreover, + * in order to achieve two memory types in a single buffer object, we + * pass a special bo flag AMDGPU_GEM_CREATE_MQD_GFX9 to instruct + * amdgpu memory functions to do so. */ if (kfd->cwsr_enabled && (q->type == KFD_QUEUE_TYPE_COMPUTE)) { mqd_mem_obj = kzalloc(sizeof(struct kfd_mem_obj), GFP_KERNEL); -- 2.17.1 _______________________________________________ amd-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/amd-gfx
