Hi Mauro,
I have checked 'do_timeout' - it's bit different that we want. I just
updated patch to use 'clock_gettime(CLOCK_MONOTONIC' to avoid
timestamps 'rollup'.
Hope it's ok. The problem is really annoying because scanning takes a
lot of time.
Without this patch command 'dvbv5-scan
us-ATSC-center-frequencies-8VSB' takes about 2 hours.
with patch it takes just 6min 45sec - which better but has a room for
optimization inside lgdt3306a.c driver - it waits about 4 sec for each
read status which I think is too long. If we have signal we should
lock in about 100-500 msec. I will check this question later.
2016-07-22 15:18 GMT-04:00 Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>:
> Hi Abylay,
>
> Em Fri, 22 Jul 2016 13:54:37 -0400
> Abylay Ospan <aospan@xxxxxxxx> escreveu:
>
>> some frontends (mentioned on lgdt3306a) wait timeout inside code like:
>> for (i = 20; i > 0; i--) {
>> msleep(50);
>>
>> If there is no-LOCK then dvbv5-scan spent a lot of time (doing 40x calls).
>> This patch introduce timeout which 4 sec * multiply. So we do not wait more
>> than 4 sec (or so) if no-LOCK.
>>
>> Signed-off-by: Abylay Ospan <aospan@xxxxxxxx>
>> ---
>> utils/dvb/dvbv5-scan.c | 15 +++++++++++++++
>> 1 file changed, 15 insertions(+)
>>
>> diff --git a/utils/dvb/dvbv5-scan.c b/utils/dvb/dvbv5-scan.c
>> index 689bc0b..1fc33d7 100644
>> --- a/utils/dvb/dvbv5-scan.c
>> +++ b/utils/dvb/dvbv5-scan.c
>> @@ -182,12 +182,23 @@ static int print_frontend_stats(struct arguments *args,
>> return 0;
>> }
>>
>> +/* return timestamp in msec */
>> +uint64_t get_timestamp()
>> +{
>> + struct timeval now;
>> + gettimeofday(&now, 0);
>> + return now.tv_sec * 1000 + now.tv_usec/1000;
>
> This is not good, as gettimeofday() is not monotonic, and may be affected
> by clock adjustments.
>
> IMHO, the best would be to adjust the do_timeout() to handle
> args->timeout_multiply.
>
> Regards,
> Mauro
>
>> +}
>> +
>> static int check_frontend(void *__args,
>> struct dvb_v5_fe_parms *parms)
>> {
>> struct arguments *args = __args;
>> int rc, i;
>> fe_status_t status;
>> + uint64_t start = get_timestamp();
>> + /* msec timeout by default 4 sec * multiply */
>> + uint64_t timeout = args->timeout_multiply * 4 * 1000;
>>
>> args->n_status_lines = 0;
>> for (i = 0; i < args->timeout_multiply * 40; i++) {
>> @@ -203,6 +214,10 @@ static int check_frontend(void *__args,
>> print_frontend_stats(args, parms);
>> if (status & FE_HAS_LOCK)
>> break;
>> +
>> + if ((get_timestamp() - start) > timeout)
>> + break;
>> +
>> usleep(100000);
>
> It would also make sense to remove the usleep here and
> use something else that would be checking timeout_flag,
> like:
>
> for (i = 1; i < 100; i++) {
> if (timeout_flag)
> break;
> usleep(1000);
> }
>
>
> --
> Thanks,
> Mauro
--
Abylay Ospan,
NetUP Inc.
http://www.netup.tv
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