[Mesa-dev] [PATCH] i965: Avoid division by zero.

[Kenneth Graunke]

On Wednesday, June 22, 2016 7:05:04 PM PDT Matt Turner wrote:
> From: Ardinartsev Nikita <ardinar23 at gmail.com>
> 
> Fixes regression introduced by af5ca43f2676bff7499f93277f908b681cb821d0
> 
> Reviewed-by: Matt Turner <mattst88 at gmail.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=95419
> ---
>  src/mesa/drivers/dri/i965/gen7_urb.c | 26 +++++++++++++++-----------
>  1 file changed, 15 insertions(+), 11 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/gen7_urb.c b/src/mesa/drivers/dri/i965/gen7_urb.c
> index 387ed2e..797d1b6 100644
> --- a/src/mesa/drivers/dri/i965/gen7_urb.c
> +++ b/src/mesa/drivers/dri/i965/gen7_urb.c
> @@ -300,17 +300,21 @@ gen7_upload_urb(struct brw_context *brw)
>        remaining_space -= vs_additional;
>        total_wants -= vs_wants;
>  
> -      unsigned hs_additional = (unsigned)
> -         round(hs_wants * (((double) remaining_space) / total_wants));
> -      hs_chunks += hs_additional;
> -      remaining_space -= hs_additional;
> -      total_wants -= hs_wants;
> -
> -      unsigned ds_additional = (unsigned)
> -         round(ds_wants * (((double) remaining_space) / total_wants));
> -      ds_chunks += ds_additional;
> -      remaining_space -= ds_additional;
> -      total_wants -= ds_wants;
> +      if (total_wants > 0) {
> +         unsigned hs_additional = (unsigned)
> +            round(hs_wants * (((double) remaining_space) / total_wants));
> +         hs_chunks += hs_additional;
> +         remaining_space -= hs_additional;
> +         total_wants -= hs_wants;
> +      }
> +
> +      if (total_wants > 0) {
> +         unsigned ds_additional = (unsigned)
> +            round(ds_wants * (((double) remaining_space) / total_wants));
> +         ds_chunks += ds_additional;
> +         remaining_space -= ds_additional;
> +         total_wants -= ds_wants;
> +      }
>  
>        gs_chunks += remaining_space;
>     }
> 

Right, the total_wants may have been entirely VS, at which point HS and
DS won't need anything.  Looks good to me!

Cc: "12.0 11.2" <mesa-stable at lists.freedesktop.org>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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