6 Sep
2022
6 Sep
'22
5:59 p.m.
On Tue, Sep 06, 2022 at 03:34:02PM +0300, Oded Gabbay wrote:
- /*
- Since the memory being mapped is a device memory it could never be in
- CPU caches.
- */
DMA_ATTR_SKIP_CPU_SYNC doesn't even apply to dma_map_resource, not sure where this wisdom comes from.
Habana driver
I hate to throw the ball at someone else, but I actually copied the code from the amdgpu driver, from amdgpu_vram_mgr_alloc_sgt() iirc. And if you remember Jason, you asked why we use this specific define in the original review you did and I replied the following (to which you agreed and that's why we added the comment):
Yes, I remember, but Christophs remark is that DMA_ATTR_SKIP_CPU_SYNC doesn't even do anything when passed to dma_map_resource().
The only attr that seems to be used is DMA_ATTR_PRIVILEGED from what I can see.
Jason