[PATCH 3/6] etnaviv: honor PIPE_TRANSFER_UNSYNCHRONIZED flag

[Wladimir J. van der Laan]

On Fri, May 19, 2017 at 11:41:09AM +0200, Lucas Stach wrote:
> This gets rid of quite a bit of CPU/GPU sync on frequent vertex buffer
> uploads and I haven't seen any of the issues mentioned in the comment,
> so this one seems stale.

Interesting. I don't quite remember what prompted adding this, it may have to
do with other hacks to support single-vertex-stream GPUs which have since been
removed, so it's likely stale.

In any case heeding PIPE_TRANSFER_UNSYNCHRONIZED makes sense. It should not just
be ignored because the driver thinks it knows better.

> Ignore the flag if there exists a temporary resource, as those ones are
> never busy.

OK. 

Reviewed-By: Wladimir J. van der Laan <laanwj at gmail.com>

> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  src/gallium/drivers/etnaviv/etnaviv_transfer.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
> 
> diff --git a/src/gallium/drivers/etnaviv/etnaviv_transfer.c b/src/gallium/drivers/etnaviv/etnaviv_transfer.c
> index 269bd498f89f..a2cd4e6234dd 100644
> --- a/src/gallium/drivers/etnaviv/etnaviv_transfer.c
> +++ b/src/gallium/drivers/etnaviv/etnaviv_transfer.c
> @@ -114,7 +114,7 @@ etna_transfer_unmap(struct pipe_context *pctx, struct pipe_transfer *ptrans)
>        }
>     }
>  
> -   if (!trans->rsc)
> +   if (!trans->rsc && !(ptrans->usage & PIPE_TRANSFER_UNSYNCHRONIZED))
>        etna_bo_cpu_fini(rsc->bo);
>  
>     pipe_resource_reference(&trans->rsc, NULL);
> @@ -260,19 +260,17 @@ etna_transfer_map(struct pipe_context *pctx, struct pipe_resource *prsc,
>                     (rsc->layout == ETNA_LAYOUT_TILED &&
>                      util_format_is_compressed(prsc->format));
>  
> -   /* Ignore PIPE_TRANSFER_UNSYNCHRONIZED and PIPE_TRANSFER_DONTBLOCK here.
> -    * It appears that Gallium operates the index/vertex buffers in a
> -    * circular fashion, and the CPU can catch up with the GPU and starts
> -    * overwriting yet-to-be-processed entries, causing rendering corruption. */
> -   uint32_t prep_flags = 0;
> +   if (trans->rsc || !(usage & PIPE_TRANSFER_UNSYNCHRONIZED)) {
> +      uint32_t prep_flags = 0;
>  
> -   if (usage & PIPE_TRANSFER_READ)
> -      prep_flags |= DRM_ETNA_PREP_READ;
> -   if (usage & PIPE_TRANSFER_WRITE)
> -      prep_flags |= DRM_ETNA_PREP_WRITE;
> +      if (usage & PIPE_TRANSFER_READ)
> +         prep_flags |= DRM_ETNA_PREP_READ;
> +      if (usage & PIPE_TRANSFER_WRITE)
> +         prep_flags |= DRM_ETNA_PREP_WRITE;
>  
> -   if (etna_bo_cpu_prep(rsc->bo, prep_flags))
> -      goto fail_prep;
> +      if (etna_bo_cpu_prep(rsc->bo, prep_flags))
> +         goto fail_prep;
> +   }
>  
>     /* map buffer object */
>     void *mapped = etna_bo_map(rsc->bo);
> -- 
> 2.11.0
> 
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