[Mesa-dev] [PATCH v1] i915: fixing driver crashes if too few vertices are submitted

[Brian Paul]

On 09/09/2015 08:16 AM, Marius Predut wrote:
> Comparison with a signed expression and unsigned value
> is converted to unsigned value, reason for minus value is interpreted
> as a big unsigned value. For this case the "for" loop
> is going into unexpected behavior.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38109
> Signed-off-by: Marius Predut <marius.predut at intel.com>
> ---
>   src/mesa/tnl_dd/t_dd_dmatmp.h | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/tnl_dd/t_dd_dmatmp.h b/src/mesa/tnl_dd/t_dd_dmatmp.h
> index 7be3954..88ecc78 100644
> --- a/src/mesa/tnl_dd/t_dd_dmatmp.h
> +++ b/src/mesa/tnl_dd/t_dd_dmatmp.h
> @@ -627,6 +627,8 @@ static void TAG(render_quads_verts)( struct gl_context *ctx,
>         LOCAL_VARS;
>         GLuint j;
>
> +      if(count%4 != 0) return;

Should be:

    if (count % 4 != 0)
       return

In addition to following our code style, this allows one to put a 
breakpoint on the return statement if one wanted to catch that 
particular condition when debugging.


> +
>         INIT(GL_TRIANGLES);
>
>         for (j = start; j < count-3; j += 4) {
> @@ -1248,7 +1250,7 @@ static GLboolean TAG(validate_render)( struct gl_context *ctx,
>   	    ok = (GLint) count < GET_SUBSEQUENT_VB_MAX_ELTS();
>   	 }
>   	 else {
> -	    ok = HAVE_TRIANGLES; /* flatshading is ok. */
> +	    ok = HAVE_TRIANGLES && (count%4 == 0); /* flatshading is ok. */

We put spaces around operators, so "count % 4" please.


>   	 }
>   	 break;
>         default:
>