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dvbsrc: improve timeout handing at locking loop

Browse source 
New approach attempts to be more accurate by measuring
the elapsed time by iteration. Also:

* Use a 10 seconds default timeout and a half a second
  polling step. New values should better match the tuning
  process on real-life scenarios.
* Correct elapsed_time computation.
* Add _retry_ioctl() to avoid bailing out on temporary
  ioctl EINTR failures (no need to check for EAGAIN cause
  we are opening the frontend on blocking mode)
* Small corrections to fail condition handling
This commit is contained in:
Reynaldo H. Verdejo Pinochet 2014-06-04 01:02:20 -04:00
parent 574b29f2c4
commit 56933d97ec
1 changed files with 57 additions and 16 deletions
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73
sys/dvb/gstdvbsrc.c
View file

@ -1,6 +1,8 @@
/* GStreamer DVB source
* Copyright (C) 2006 Zaheer Abbas Merali <zaheerabbas at merali
* dot org>
* Copyright (C) 2014 Samsung Electronics. All rights reserved.
* @Author: Reynaldo H. Verdejo Pinochet <r.verdejo@sisa.samsung.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
@ -205,7 +207,7 @@ enum
#define DEFAULT_INVERSION INVERSION_ON
#define DEFAULT_STATS_REPORTING_INTERVAL 100
#define DEFAULT_TIMEOUT 1000000 /* 1 second */
#define DEFAULT_TUNING_TIMEOUT 10 * GST_MSECOND /* 10 milliseconds */
#define DEFAULT_TUNING_TIMEOUT 10 * GST_SECOND /* 10 seconds */
#define DEFAULT_DVB_BUFFER_SIZE (10*188*1024) /* kernel default is 8192 */
#define DEFAULT_BUFFER_SIZE 8192 /* not a property */
#define DEFAULT_DELSYS SYS_UNDEFINED
@ -470,6 +472,8 @@ static gboolean gst_dvbsrc_tune_fe (GstDvbSrc * object);
static void gst_dvbsrc_set_pes_filters (GstDvbSrc * object);
static void gst_dvbsrc_unset_pes_filters (GstDvbSrc * object);
static inline int gst_dvbsrc_retry_ioctl (int fd, unsigned long req,
void *data);
static GstStaticPadTemplate ts_src_factory = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
@ -753,6 +757,29 @@ gst_dvbsrc_init (GstDvbSrc * object)
object->tuning_timeout = DEFAULT_TUNING_TIMEOUT;
}
/**
* This loop should be safe enough considering:
*
* 1.- EINTR suggest the next ioctl might succeed
* 2.- It's highly unlikely you will end up spining
* before your entire system goes nuts due to
* the massive number of interrupts.
*
* We don't check for EAGAIN here cause we are opening
* the frontend in blocking mode.
*/
static inline int
gst_dvbsrc_retry_ioctl (int fd, unsigned long req, void *data)
{
int ret;
do
ret = ioctl (fd, req, data);
while (ret == -1 && errno == EINTR);
return ret;
}
static void
gst_dvbsrc_set_pids (GstDvbSrc * dvbsrc, const gchar * pid_string)
{
@ -1658,8 +1685,8 @@ gst_dvbsrc_tune_fe (GstDvbSrc * object)
fe_status_t status;
struct dtv_properties props;
struct dtv_property dvb_prop[NUM_DTV_PROPS];
GstClockTimeDiff timeout_step = 1 * GST_USECOND;
GstClockTime elapsed_time;
GstClockTimeDiff elapsed_time, timeout_step = 500 * GST_MSECOND;
GstClockTime start;
GST_DEBUG_OBJECT (object, "Starting the frontend tuning process");
@ -1674,7 +1701,7 @@ gst_dvbsrc_tune_fe (GstDvbSrc * object)
props.num = 1;
props.props = dvb_prop;
if (ioctl (object->fd_frontend, FE_GET_PROPERTY, &props) < 0) {
if (gst_dvbsrc_retry_ioctl (object->fd_frontend, FE_GET_PROPERTY, &props)) {
GST_WARNING_OBJECT (object, "Error enumerating delsys: %s",
g_strerror (errno));
@ -1708,38 +1735,52 @@ gst_dvbsrc_tune_fe (GstDvbSrc * object)
props.num = 1;
props.props = dvb_prop;
if (ioctl (object->fd_frontend, FE_SET_PROPERTY, &props) < 0) {
if (gst_dvbsrc_retry_ioctl (object->fd_frontend, FE_SET_PROPERTY, &props)) {
GST_WARNING_OBJECT (object, "Error resetting tuner: %s",
g_strerror (errno));
}
memset (dvb_prop, 0, sizeof (dvb_prop));
if (!gst_dvbsrc_set_fe_params (object, &props)) {
GST_WARNING_OBJECT (object, "Could not set frontend params");
goto fail;
}
GST_DEBUG_OBJECT (object, "Setting %d properties", props.num);
if (ioctl (object->fd_frontend, FE_SET_PROPERTY, &props) < 0) {
GST_WARNING_OBJECT (object, "Error tuning channel: %s", g_strerror (errno));
if (gst_dvbsrc_retry_ioctl (object->fd_frontend, FE_SET_PROPERTY, &props)) {
GST_WARNING_OBJECT (object, "Error tuning channel: %s (%d)",
g_strerror (errno), errno);
goto fail;
}
g_signal_emit (object, gst_dvbsrc_signals[SIGNAL_TUNING_START], 0);
elapsed_time = 0;
if (gst_dvbsrc_retry_ioctl (object->fd_frontend, FE_READ_STATUS, &status)) {
GST_WARNING_OBJECT (object, "Failed querying frontend for tuning status:"
" %s (%d)", g_strerror (errno), errno);
goto fail_with_signal;
}
/* signal locking loop */
do {
if (ioctl (object->fd_frontend, FE_READ_STATUS, &status) == -1) {
GST_WARNING_OBJECT (object, "Failed querying frontend for tuning status");
goto fail_with_signal;
}
elapsed_time = 0;
start = gst_util_get_timestamp ();
while (!(status & FE_HAS_LOCK) && elapsed_time <= object->tuning_timeout) {
if (gst_poll_wait (poll_set, timeout_step) == -1)
goto fail_with_signal;
if (gst_dvbsrc_retry_ioctl (object->fd_frontend, FE_READ_STATUS, &status)) {
GST_WARNING_OBJECT (object, "Failed querying frontend for tuning status"
" %s (%d)", g_strerror (errno), errno);
goto fail_with_signal;
}
gst_dvbsrc_output_frontend_stats (object);
GST_INFO_OBJECT (object, "Trying to get lock");
/* keep retrying forever if tuning_timeout = 0 */
if (object->tuning_timeout)
elapsed_time += timeout_step;
} while (!(status & FE_HAS_LOCK) && elapsed_time < object->tuning_timeout);
elapsed_time = GST_CLOCK_DIFF (start, gst_util_get_timestamp ());
GST_LOG_OBJECT (object,
"Tuning. Time elapsed %" G_GUINT64_FORMAT " Limit %" G_GUINT64_FORMAT,
elapsed_time, object->tuning_timeout);
}
if (!(status & FE_HAS_LOCK)) {
GST_WARNING_OBJECT (object,