Re: [RFC 0/6] drm/fences: add in-fences to DRM

Maarten Lankhorst
2016-03-24T07:20:57Z

Hey,

Op 23-03-16 om 19:47 schreef Gustavo Padovan:
> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
> Hi,
>
> This is a first proposal to discuss the addition of in-fences support
> to DRM. It adds a new struct to fence.c to abstract the use of sync_file
> in DRM drivers. The new struct fence_collection contains a array with all
> fences that a atomic commit needs to wait on
>
> /**
> * struct fence_collection - aggregate fences together
> * @num_fences: number of fence in the collection.
> * @user_data: user data.
> * @func: user callback to put user data.
> * @fences: array of @num_fences fences.
> */
> struct fence_collection {
> int num_fences;
> void *user_data;
> collection_put_func_t func;
> struct fence *fences[];
> };
>
>
> The fence_collection is allocated and filled by sync_file_fences_get() and
> atomic_commit helpers can use fence_collection_wait() to wait the fences to
> signal.
>
> These patches depends on the sync ABI rework:
>
> https://www.spinics.net/lists/dri-devel/msg102795.html
>
> and the patch to de-stage the sync framework:
>
> https://www.spinics.net/lists/dri-devel/msg102799.html
>
>
> I also hacked together some sync support into modetest for testing:
>
> https://git.collabora.com/cgit/user/padovan/libdrm.git/log/?h=atomic
>
Why did you choose to add fence_collection, rather than putting sync_file in state?

There used to be a sync_fence_wait function, which would mean you'd have everything you need.

~Maarten