On Fri, Jun 26, 2020 at 2:21 PM Lionel Landwerlin lionel.g.landwerlin@intel.com wrote:
Trying to explain a bit how this thing works. In my opinion diagrams are a bit easier to understand than words.
kerneldoc supports in-line DOT graphs, see e.g.
https://dri.freedesktop.org/docs/drm/gpu/drm-kms.html#overview
If that doesn't work, then you can include a full-blown svg too.
And yes for this a quick DOT graph that explains how things connect sound like the perfect use of a diagramm.
Cheers, Daniel
Signed-off-by: Lionel Landwerlin lionel.g.landwerlin@intel.com
drivers/dma-buf/dma-fence-chain.c | 37 +++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+)
diff --git a/drivers/dma-buf/dma-fence-chain.c b/drivers/dma-buf/dma-fence-chain.c index 3d123502ff12..ac90ddf37b55 100644 --- a/drivers/dma-buf/dma-fence-chain.c +++ b/drivers/dma-buf/dma-fence-chain.c @@ -9,6 +9,43 @@
#include <linux/dma-fence-chain.h>
+/**
- DOC: DMA fence chains overview
- DMA fence chains, represented by &struct dma_fence_chain, are a kernel
- internal synchronization primitive providing a wrapping mechanism of other
- DMA fences in the form a single link list.
- One of the use case of this primitive is to implement Vulkan timeline
- semaphores (see VK_KHR_timeline_semaphore extension or Vulkan specification
- 1.2).
- Each DMA fence chain item wraps 2 items :
- A previous DMA fence.
- A DMA fence associated to the current &struct dma_fence_chain.
- A DMA fence chain becomes signaled when its previous fence as well as its
- associated fence are signaled. If a chain of dma fence chains is created,
- this property recurses, meaning that any dma fence chain element in the
- list becomes signaled only if its associated fence and all the previous
- fences in the chain are also signaled.
- A DMA fence chain's seqno is specified through dma_fence_chain_init(). This
- value is lower bound to the seqno of the previous fence to ensure the chain
- is monotically increasing.
- By traversing the chain's linked list, one can compute a seqno number
- associated with the chain such that is the highest number for which all
- previous fences have signaled.
- One can also traverse the chain's linked list to find a &struct
- dma_fence_chain that when signaled guarantees that all previous fences in
- the chain are signaled. dma_fence_chain_find_seqno() provides this
- functionality.
- */
static bool dma_fence_chain_enable_signaling(struct dma_fence *fence);
/**
2.27.0
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