V4L/DVB: pvrusb2: Enforce a 300msec stabilization interval during stream strart

Martin Dauskardt <martin.dauskardt@gmx.de> has determined that the
encoder has a much better chance of starting cleanly if we
deliberately hold off starting it util the video digitizer has had a
chance to run for at least 300msec first.  These changes implement an
enforced 300msec wait in the state machine that orchestrates streaming
start / stop.

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 49 insertions, 5 deletions

diff --git a/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h b/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h
index de5485f506b..cb4057bb07a 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h
+++ b/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h
@@ -233,8 +233,9 @@ struct pvr2_hdw {
         int state_encoder_waitok;     /* Encoder pre-wait done */
         int state_encoder_runok;      /* Encoder has run for >= .25 sec */
         int state_decoder_run;        /* Decoder is running */
+        int state_decoder_ready;      /* Decoder is stabilized & streamable */
         int state_usbstream_run;      /* FX2 is streaming */
-        int state_decoder_quiescent;  /* Decoder idle for > 50msec */
+        int state_decoder_quiescent;  /* Decoder idle for minimal interval */
         int state_pipeline_config;    /* Pipeline is configured */
         int state_pipeline_req;       /* Somebody wants to stream */
         int state_pipeline_pause;     /* Pipeline must be paused */
@@ -255,9 +256,16 @@ struct pvr2_hdw {
         void (*state_func)(void *);
         void *state_data;
 
-        /* Timer for measuring decoder settling time */
+        /* Timer for measuring required decoder settling time before we're
+           allowed to fire it up again. */
         struct timer_list quiescent_timer;
 
+        /* Timer for measuring decoder stabilization time, which is the
+           amount of time we need to let the decoder run before we can
+           trust its output (otherwise the encoder might see garbage and
+           then fail to start correctly). */
+        struct timer_list decoder_stabilization_timer;
+
         /* Timer for measuring encoder pre-wait time */
         struct timer_list encoder_wait_timer;
 
diff --git a/drivers/media/video/pvrusb2/pvrusb2-hdw.c b/drivers/media/video/pvrusb2/pvrusb2-hdw.c
index ad9ed51f7b9..79b2a544ccb 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-hdw.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-hdw.c
@@ -48,6 +48,10 @@
    before we are allowed to start it running. */
 #define TIME_MSEC_DECODER_WAIT 50
 
+/* This defines a minimum interval that the decoder must be allowed to run
+   before we can safely begin using its streaming output. */
+#define TIME_MSEC_DECODER_STABILIZATION_WAIT 300
+
 /* This defines a minimum interval that the encoder must remain quiet
    before we are allowed to configure it.  I had this originally set to
    50msec, but Martin Dauskardt <martin.dauskardt@gmx.de> reports that
@@ -334,6 +338,7 @@ static int pvr2_hdw_get_eeprom_addr(struct pvr2_hdw *hdw);
 static void pvr2_hdw_internal_find_stdenum(struct pvr2_hdw *hdw);
 static void pvr2_hdw_internal_set_std_avail(struct pvr2_hdw *hdw);
 static void pvr2_hdw_quiescent_timeout(unsigned long);
+static void pvr2_hdw_decoder_stabilization_timeout(unsigned long);
 static void pvr2_hdw_encoder_wait_timeout(unsigned long);
 static void pvr2_hdw_encoder_run_timeout(unsigned long);
 static int pvr2_issue_simple_cmd(struct pvr2_hdw *,u32);
@@ -2462,6 +2467,11 @@ struct pvr2_hdw *pvr2_hdw_create(struct usb_interface *intf,
         hdw->quiescent_timer.data = (unsigned long)hdw;
         hdw->quiescent_timer.function = pvr2_hdw_quiescent_timeout;
 
+        init_timer(&hdw->decoder_stabilization_timer);
+        hdw->decoder_stabilization_timer.data = (unsigned long)hdw;
+        hdw->decoder_stabilization_timer.function =
+                pvr2_hdw_decoder_stabilization_timeout;
+
         init_timer(&hdw->encoder_wait_timer);
         hdw->encoder_wait_timer.data = (unsigned long)hdw;
         hdw->encoder_wait_timer.function = pvr2_hdw_encoder_wait_timeout;
@@ -2675,6 +2685,7 @@ struct pvr2_hdw *pvr2_hdw_create(struct usb_interface *intf,
  fail:
         if (hdw) {
                 del_timer_sync(&hdw->quiescent_timer);
+                del_timer_sync(&hdw->decoder_stabilization_timer);
                 del_timer_sync(&hdw->encoder_run_timer);
                 del_timer_sync(&hdw->encoder_wait_timer);
                 if (hdw->workqueue) {
@@ -2742,6 +2753,7 @@ void pvr2_hdw_destroy(struct pvr2_hdw *hdw)
                 hdw->workqueue = NULL;
         }
         del_timer_sync(&hdw->quiescent_timer);
+        del_timer_sync(&hdw->decoder_stabilization_timer);
         del_timer_sync(&hdw->encoder_run_timer);
         del_timer_sync(&hdw->encoder_wait_timer);
         if (hdw->fw_buffer) {
@@ -4453,7 +4465,7 @@ static int state_check_enable_encoder_run(struct pvr2_hdw *hdw)
 
         switch (hdw->pathway_state) {
         case PVR2_PATHWAY_ANALOG:
-                if (hdw->state_decoder_run) {
+                if (hdw->state_decoder_run && hdw->state_decoder_ready) {
                         /* In analog mode, if the decoder is running, then
                            run the encoder. */
                         return !0;
@@ -4520,6 +4532,17 @@ static void pvr2_hdw_quiescent_timeout(unsigned long data)
 }
 
 
+/* Timeout function for decoder stabilization timer. */
+static void pvr2_hdw_decoder_stabilization_timeout(unsigned long data)
+{
+        struct pvr2_hdw *hdw = (struct pvr2_hdw *)data;
+        hdw->state_decoder_ready = !0;
+        trace_stbit("state_decoder_ready", hdw->state_decoder_ready);
+        hdw->state_stale = !0;
+        queue_work(hdw->workqueue, &hdw->workpoll);
+}
+
+
 /* Timeout function for encoder wait timer. */
 static void pvr2_hdw_encoder_wait_timeout(unsigned long data)
 {
@@ -4558,8 +4581,13 @@ static int state_eval_decoder_run(struct pvr2_hdw *hdw)
                 }
                 hdw->state_decoder_quiescent = 0;
                 hdw->state_decoder_run = 0;
-                /* paranoia - solve race if timer just completed */
+                /* paranoia - solve race if timer(s) just completed */
                 del_timer_sync(&hdw->quiescent_timer);
+                /* Kill the stabilization timer, in case we're killing the
+                   encoder before the previous stabilization interval has
+                   been properly timed. */
+                del_timer_sync(&hdw->decoder_stabilization_timer);
+                hdw->state_decoder_ready = 0;
         } else {
                 if (!hdw->state_decoder_quiescent) {
                         if (!timer_pending(&hdw->quiescent_timer)) {
@@ -4597,10 +4625,16 @@ static int state_eval_decoder_run(struct pvr2_hdw *hdw)
                 if (hdw->flag_decoder_missed) return 0;
                 if (pvr2_decoder_enable(hdw,!0) < 0) return 0;
                 hdw->state_decoder_quiescent = 0;
+                hdw->state_decoder_ready = 0;
                 hdw->state_decoder_run = !0;
+                hdw->decoder_stabilization_timer.expires =
+                        jiffies +
+                        (HZ * TIME_MSEC_DECODER_STABILIZATION_WAIT / 1000);
+                add_timer(&hdw->decoder_stabilization_timer);
         }
         trace_stbit("state_decoder_quiescent",hdw->state_decoder_quiescent);
         trace_stbit("state_decoder_run",hdw->state_decoder_run);
+        trace_stbit("state_decoder_ready", hdw->state_decoder_ready);
         return !0;
 }
 
@@ -4798,7 +4832,8 @@ static unsigned int pvr2_hdw_report_unlocked(struct pvr2_hdw *hdw,int which,
                         buf,acnt,
                         "worker:%s%s%s%s%s%s%s",
                         (hdw->state_decoder_run ?
-                         " <decode:run>" :
+                         (hdw->state_decoder_ready ?
+                          "<decode:run>" : " <decode:start>") :
                          (hdw->state_decoder_quiescent ?
                           "" : " <decode:stop>")),
                         (hdw->state_decoder_quiescent ?
diff --git a/drivers/media/video/pvrusb2/pvrusb2-hdw.h b/drivers/media/video/pvrusb2/pvrusb2-hdw.h
index 56e70eae20c..51d3009ab57 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-hdw.h
+++ b/drivers/media/video/pvrusb2/pvrusb2-hdw.h
@@ -306,6 +306,7 @@ struct pvr2_hdw_debug_info {
         int state_encoder_ok;
         int state_encoder_run;
         int state_decoder_run;
+        int state_decoder_ready;
         int state_usbstream_run;
         int state_decoder_quiescent;
         int state_pipeline_config;