[igt-dev] [RESEND PATCH v6 i-g-t] tests/kms_flip: Skip VBlank tests in modules without VBlank

[Chris Wilson]

Quoting Rodrigo Siqueira (2019-04-18 15:01:49)
> +bool kms_has_vblank(int fd)
> +{
> +       drmVBlank dummy_vbl;
> +
> +       memset(&dummy_vbl, 0, sizeof(drmVBlank));
> +       dummy_vbl.request.type = DRM_VBLANK_RELATIVE;
> +
> +       drmWaitVBlank(fd, &dummy_vbl);
> +       return (errno != EOPNOTSUPP);

errno is only set on error. It is conceivably that drmWaitVBlank()
suceeed but errno is still set to EOPNOTSUPP from an earlier syscall.
-Chris