[RFC v2 04/12] sync: Add support for DMA fences

[Adam Jackson]

On Wed, 2017-09-27 at 01:19 -0400, Louis-Francis Ratté-Boulianne wrote:

> @@ -1931,6 +1959,9 @@ ProcSyncTriggerFence(ClientPtr client)
>      if (rc != Success)
>          return rc;
>  
> +    if (pFence->type == SYNC_FENCE_DMA)
> +        return BadMatch;
> +
>      miSyncTriggerFence(pFence);
>  
>      return Success;

This is a bad pattern, the dispatch code shouldn't need to know
anything about fence types. I think this should instead change
miSyncTriggerFence (and pFence->funcs.SetTriggered) to return a Status,
and have ProcSyncTriggerFence end with 'return miSyncTriggerFence()'.

> @@ -1950,7 +1981,8 @@ ProcSyncResetFence(ClientPtr client)
>      if (rc != Success)
>          return rc;
>  
> -    if (pFence->funcs.CheckTriggered(pFence) != TRUE)
> +    if (pFence->type == SYNC_FENCE_DMA ||
> +        pFence->funcs.CheckTriggered(pFence) != TRUE)
>          return BadMatch;
>  
>      pFence->funcs.Reset(pFence);

Likewise here.

> diff --git a/miext/sync/misync.h b/miext/sync/misync.h
> index b3838f1e2..c32e4c961 100644
> --- a/miext/sync/misync.h
> +++ b/miext/sync/misync.h
> @@ -28,6 +28,10 @@
>  #ifndef _MISYNC_H_
>  #define _MISYNC_H_
>  
> +/* Sync fence types */
> +#define SYNC_FENCE_SHM          0
> +#define SYNC_FENCE_DMA          1
> +
>  typedef struct _SyncFence SyncFence;
>  typedef struct _SyncTrigger SyncTrigger;
>  
> @@ -73,6 +77,9 @@ extern _X_EXPORT SyncScreenFuncsPtr miSyncGetScreenFuncs(ScreenPtr pScreen);
>  extern _X_EXPORT Bool
>   miSyncSetup(ScreenPtr pScreen);
>  
> +extern _X_EXPORT int
> +miSyncGetFenceType(SyncFence * pFence);
> +
>  Bool
>  miSyncFenceCheckTriggered(SyncFence * pFence);
>  

... and ...

> diff --git a/miext/sync/misyncstr.h b/miext/sync/misyncstr.h
> index 2eab2aa57..6d97894f0 100644
> --- a/miext/sync/misyncstr.h
> +++ b/miext/sync/misyncstr.h
> @@ -57,6 +57,7 @@ struct _SyncFence {
>      ScreenPtr pScreen;          /* Screen of this fence object */
>      SyncFenceFuncsRec funcs;    /* Funcs for performing ops on fence */
>      Bool triggered;             /* fence state */
> +    unsigned char type;         /* fence type */
>      PrivateRec *devPrivates;    /* driver-specific per-fence data */
>  };
>  

... with all that changed, I think you can avoid needing to add the
'type' field and GetFenceType accessor at all.

- ajax