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demo: Properly handle low samplerates 

A "low samplerate" in this case means anything where
samples_todo is less than SAMPLES_PER_FRAME. This case
wasn't handled properly before, resulting in wrong
amounts of data being sent out.
This commit is contained in:
Soeren Apel 2017-10-11 18:14:56 +02:00 committed by Uwe Hermann
parent e0b6855bd4
commit 767ca13532
3 changed files with 23 additions and 6 deletions
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1
src/hardware/demo/api.c
View File

@ -400,6 +400,7 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi)
devc = sdi->priv;
devc->sent_samples = 0;
devc->sent_frame_samples = 0;
/*
* Determine the numbers of logic and analog channels that are

27
src/hardware/demo/protocol.c
View File

@ -460,9 +460,6 @@ SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data)
samples_todo = (todo_us * devc->cur_samplerate + G_USEC_PER_SEC - 1)
/ G_USEC_PER_SEC;
if (SAMPLES_PER_FRAME > 0)
samples_todo = SAMPLES_PER_FRAME;
if (devc->limit_samples > 0) {
if (devc->limit_samples < devc->sent_samples)
samples_todo = 0;
@ -470,6 +467,16 @@ SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data)
samples_todo = devc->limit_samples - devc->sent_samples;
}
if (samples_todo == 0)
return G_SOURCE_CONTINUE;
#if (SAMPLES_PER_FRAME > 0) /* Avoid "comparison < 0 always false" warning. */
/* Never send more samples than a frame can fit... */
samples_todo = MIN(samples_todo, SAMPLES_PER_FRAME);
/* ...or than we need to finish the current frame. */
samples_todo = MIN(samples_todo, SAMPLES_PER_FRAME - devc->sent_frame_samples);
#endif
/* Calculate the actual time covered by this run back from the sample
* count, rounded towards zero. This avoids getting stuck on a too-low
* time delta with no samples being sent due to round-off.
@ -520,8 +527,16 @@ SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data)
return G_SOURCE_REMOVE;
}
devc->sent_samples += samples_todo;
devc->sent_frame_samples += samples_todo;
devc->spent_us += todo_us;
#if (SAMPLES_PER_FRAME > 0) /* Avoid "comparison >= 0 always true" warning. */
if (devc->sent_frame_samples >= SAMPLES_PER_FRAME) {
std_session_send_frame_end(sdi);
devc->sent_frame_samples = 0;
}
#endif
if ((devc->limit_samples > 0 && devc->sent_samples >= devc->limit_samples)
|| (limit_us > 0 && devc->spent_us >= limit_us)) {
@ -540,10 +555,10 @@ SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data)
sr_dbg("Requested number of samples reached.");
sr_dev_acquisition_stop(sdi);
} else {
if (SAMPLES_PER_FRAME > 0) {
std_session_send_frame_end(sdi);
#if (SAMPLES_PER_FRAME > 0)
if (devc->sent_frame_samples == 0)
std_session_send_frame_begin(sdi);
}
#endif
}
return G_SOURCE_CONTINUE;

1
src/hardware/demo/protocol.h
View File

@ -41,6 +41,7 @@ struct dev_context {
uint64_t limit_samples;
uint64_t limit_msec;
uint64_t sent_samples;
uint64_t sent_frame_samples; /* Number of samples that were sent for current frame. */
int64_t start_us;
int64_t spent_us;
uint64_t step;