[Mesa-dev] [RFC PATCH 2/2] main/format: skip format conversion if src and dst format are equal

[Erik Faye-Lund]

On Wed, Aug 16, 2017 at 8:32 PM, Karol Herbst <karolherbst at gmail.com> wrote:
> Fixes 'KHR-GL45.copy_image.functional' on Nouveau
>
> Signed-off-by: Karol Herbst <karolherbst at gmail.com>
> ---
>  src/mesa/main/format_utils.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/main/format_utils.c b/src/mesa/main/format_utils.c
> index d16d69c379..a3ddaebb2e 100644
> --- a/src/mesa/main/format_utils.c
> +++ b/src/mesa/main/format_utils.c
> @@ -485,7 +485,11 @@ _mesa_format_convert(void *void_dst, uint32_t dst_format, size_t dst_stride,
>
>     assert(src_integer == dst_integer);
>
> -   if (src_integer && dst_integer) {
> +   /* do a simply memcpy if applicable */
> +   if (dst_format == src_format && dst_stride == src_stride &&
> +       !dst_format_is_mesa_array_format && !rebase_swizzle) {
> +      memcpy(dst, src, src_stride * height);
> +   } else if (src_integer && dst_integer) {

This sounds like it just makes the bug harder to trigger. What if the
format is the same, but the pitch isn't the same? Won't that cause the
same issue, just without the CTS picking it up?