Code is expecing to observe the same number of buffers returned from dma_map_sg() function compared to sg_alloc_table_from_pages(). This doesn't hold true universally especially for systems with IOMMU.
The hardware actually needs the dma_address on a page by page basis. Joining multiple consecutive pages into one entry is just additional overhead which we don't need.
Signed-off-by: Sinan Kaya okaya@codeaurora.org --- drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index af1b879..91abe1a 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -1948,6 +1948,9 @@ int amdgpu_device_init(struct amdgpu_device *adev, /* init the mode config */ drm_mode_config_init(adev->ddev);
+ /* limit scatter-gather buffer size to PAGE_SIZE */ + dma_set_max_seg_size(adev->dev, PAGE_SIZE); + r = amdgpu_device_ip_init(adev); if (r) { /* failed in exclusive mode due to timeout */