On 26/04/2021 00:54, Deborah Brouwer wrote:
> Measure the interval since the last audio rate control message in
> nanoseconds instead of seconds. Increasing the precision catches audio
> rate messages that are late by less than a second.
>
> Signed-off-by: Deborah Brouwer <deborahbrouwer3563@xxxxxxxxx>
> ---
> utils/cec-follower/cec-processing.cpp | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/utils/cec-follower/cec-processing.cpp b/utils/cec-follower/cec-processing.cpp
> index 93db4059..243c9d09 100644
> --- a/utils/cec-follower/cec-processing.cpp
> +++ b/utils/cec-follower/cec-processing.cpp
> @@ -29,8 +29,8 @@
> /* Time between each polling message sent to a device */
> #define POLL_PERIOD 15000
>
> -/* The maximum interval in seconds between audio rate messages as defined in the spec */
> -#define MAX_AUD_RATE_MSG_INTERVAL 2
> +/* The maximum interval in nanoseconds between audio rate messages as defined in the spec */
> +#define MAX_AUD_RATE_MSG_INTERVAL 2000000000
It's a bit easier to read if you write this as:
#define MAX_AUD_RATE_MSG_INTERVAL_NS (2 * 1000000000ULL)
It's helpful to add the unit as a suffix to the define name and to
write it as a multiplication of seconds times nsecs_per_sec.
Also ULL helps cast the expression to an unsigned long long (64 bit).
Not strictly necessary, but since we check intervals using __u64 it
doesn't hurt either.
Regards,
Hans
>
> struct cec_enum_values {
> const char *type_name;
> @@ -241,7 +241,8 @@ static void aud_rate_msg_interval_check(__u64 ts_new, __u64 ts_old)
> * turned off the audio rate control.
> */
> if (ts_old) {
> - unsigned interval = (ts_new - ts_old) / 1000000000;
> + __u64 interval = ts_new - ts_old;
> +
> if (interval > MAX_AUD_RATE_MSG_INTERVAL) {
> warn("The interval between Audio Rate Control messages was greater\n");
> warn("than the Maxiumum Audio Rate Message Interval (2s).\n");
>
