Re: [PATCH] drm/amdgpu: fix AGP addressing when GART is not at 0

[Christian König]

Am 10.11.23 um 15:47 schrieb Alex Deucher:
This worked by luck if the GART aperture ended up at 0.  When
we ended up moving GART on some chips, the GART aperture ended
up offsetting the the AGP address since the resource->start is
a GART offset, not an MC address.  Fix this by moving the AGP
address setup into amdgpu_bo_gpu_offset_no_check().
Reported-by: Jesse Zhang <jesse.zh...@amd.com>
Reported-by: Yifan Zhang <yifan1.zh...@amd.com>
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
Cc: christian.koe...@amd.com
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 10 +++++++---
  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    |  4 +---
  2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index cef920a93924..1b3e97522838 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1527,10 +1527,14 @@ u64 amdgpu_bo_gpu_offset(struct amdgpu_bo *bo)
  u64 amdgpu_bo_gpu_offset_no_check(struct amdgpu_bo *bo)
  {
        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
-       uint64_t offset;
+       uint64_t offset, addr;
  
-	offset = (bo->tbo.resource->start << PAGE_SHIFT) +
-                amdgpu_ttm_domain_start(adev, bo->tbo.resource->mem_type);
+       addr = amdgpu_gmc_agp_addr(&bo->tbo);

IIRC you must check bo->tbo.resource->mem_type before calling 
amdgpu_gmc_agp_addr().

Regards,
Christian.

+       if (addr != AMDGPU_BO_INVALID_OFFSET)
+               offset = addr;
+       else
+               offset = (bo->tbo.resource->start << PAGE_SHIFT) +
+                       amdgpu_ttm_domain_start(adev, 
bo->tbo.resource->mem_type);
  
  	return amdgpu_gmc_sign_extend(offset);
  }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 05991c5c8ddb..ab4a762aed5b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -959,10 +959,8 @@ int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
                return 0;
  
  	addr = amdgpu_gmc_agp_addr(bo);
-       if (addr != AMDGPU_BO_INVALID_OFFSET) {
-               bo->resource->start = addr >> PAGE_SHIFT;
+       if (addr != AMDGPU_BO_INVALID_OFFSET)
                return 0;
-       }
  
  	/* allocate GART space */
        placement.num_placement = 1;