[alsa-devel] [RFC PATCH 6/7] uapi: sound: Avoid using timespec for struct snd_ctl_elem_value

[Arnd Bergmann]

On Thu, Sep 21, 2017 at 8:18 AM, Baolin Wang <baolin.wang at linaro.org> wrote:
> The struct snd_ctl_elem_value will use 'timespec' type variables to record
> timestamp, which is not year 2038 safe on 32bits system.
>
> Since there are no drivers will implemented the tstamp member of the
> struct snd_ctl_elem_value, and also the stucture size will not be changed
> if we change timespec to s64 for tstamp member of struct snd_ctl_elem_value.
>
> Thus we can simply change timespec to s64 for tstamp member to avoid
> using the type which is not year 2038 safe on 32bits system.
>
> Signed-off-by: Baolin Wang <baolin.wang at linaro.org>
> ---
>  include/uapi/sound/asound.h |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
> index 1949923..71bce52 100644
> --- a/include/uapi/sound/asound.h
> +++ b/include/uapi/sound/asound.h
> @@ -943,8 +943,8 @@ struct snd_ctl_elem_value {
>                 } bytes;
>                 struct snd_aes_iec958 iec958;
>         } value;                /* RO */
> -       struct timespec tstamp;
> -       unsigned char reserved[128-sizeof(struct timespec)];
> +       struct { s64 tv_sec; s64 tv_nsec; } tstamp;
> +       unsigned char reserved[128-sizeof(struct { s64 tv_sec; s64 tv_nsec; })];
>  };

Maybe we should enforce that nobody uses the timespec field, by
enclosing it in #ifdef __KERNEL__ (with a matching length below it);

       Arnd