Place all recording functionality on pcmrec thread to serialize all recording operations. Button mash problems should be ruled out of pcm_record.c. Add additional lightweight checks by default and display any warnings that occurred during recording in first line of recording screen when they occur by blinking back and forth from warning display to normal line (Warning: <hex bitmask>). Warnings are cleared when beginning a new recording so write the number down if you see it and file a report. Add heavier checks when PCMREC_PARANOID is defined in the player config header (encoders and pcm_record must be aware of the define since it changes the chunk header format). These checks are mainly concerned with things that may cause skipping but also add unwanted overhead for normal operation. Best used with logf enabled.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11705 a1c6a512-1295-4272-9138-f99709370657

4 files changed, 478 insertions, 262 deletions

diff --git a/firmware/export/audio.h b/firmware/export/audio.h
index 3edbfe155d..6a98d6f4c5 100644
--- a/firmware/export/audio.h
+++ b/firmware/export/audio.h
@@ -39,16 +39,17 @@
 #define audio_play(x) sim_audio_play(x)
 #endif
 
-#define AUDIO_STATUS_PLAY 1
-#define AUDIO_STATUS_PAUSE 2
-#define AUDIO_STATUS_RECORD 4
-#define AUDIO_STATUS_PRERECORD 8
-#define AUDIO_STATUS_ERROR 16
+#define AUDIO_STATUS_PLAY       0x0001
+#define AUDIO_STATUS_PAUSE      0x0002
+#define AUDIO_STATUS_RECORD     0x0004
+#define AUDIO_STATUS_PRERECORD  0x0008
+#define AUDIO_STATUS_ERROR      0x0010
+#define AUDIO_STATUS_WARNING    0x0020
 
-#define AUDIOERR_DISK_FULL 1
+#define AUDIOERR_DISK_FULL      1
 
-#define AUDIO_GAIN_LINEIN    0
-#define AUDIO_GAIN_MIC       1
+#define AUDIO_GAIN_LINEIN       0
+#define AUDIO_GAIN_MIC          1
 
 
 struct audio_debug
diff --git a/firmware/export/enc_base.h b/firmware/export/enc_base.h
index 1be796ec8f..8d1e6fa11e 100644
--- a/firmware/export/enc_base.h
+++ b/firmware/export/enc_base.h
@@ -152,10 +152,18 @@ struct encoder_config
 #define CHUNKF_ERROR    0x80000000 /* An error has occured (passed to/
                                       from encoder). Use the sign bit to
                                       check (long)flags < 0.               */
+#define CHUNKF_ALLFLAGS 0x80000033
 
 /* Header at the beginning of every encoder chunk */
+#ifdef PCMREC_PARANOID
+#define ENC_CHUNK_MAGIC H_TO_BE32(('P' << 24) | ('T' << 16) | ('Y' << 8) | 'R')
+#endif
 struct enc_chunk_hdr
 {
+#ifdef PCMREC_PARANOID
+    unsigned long id;         /* overflow detection - 'PTYR' - acronym for
+                                 "PTYR Tells You Right" ;)                 */
+#endif
     unsigned long flags;      /* in/out: flags used by encoder and file
                                          writing                           */
     size_t        enc_size;   /* out:    amount of encoder data written to
diff --git a/firmware/export/pcm_record.h b/firmware/export/pcm_record.h
index f6dddb3424..865a37fc70 100644
--- a/firmware/export/pcm_record.h
+++ b/firmware/export/pcm_record.h
@@ -25,6 +25,37 @@
 #define DMA_REC_ERROR_SPDIF     (-2)
 #endif
 
+/** Warnings **/
+/* pcm (dma) buffer has overflowed */
+#define PCMREC_W_PCM_BUFFER_OVF         0x00000001
+/* encoder output buffer has overflowed */
+#define PCMREC_W_ENC_BUFFER_OVF         0x00000002
+#ifdef PCMREC_PARANOID
+/* dma write position alignment incorrect */
+#define PCMREC_W_DMA_WR_POS_ALIGN       0x00000004
+/* pcm read position changed at some point not under control of recording */
+#define PCMREC_W_PCM_RD_POS_TRASHED     0x00000008
+/* dma write position changed at some point not under control of recording */
+#define PCMREC_W_DMA_WR_POS_TRASHED     0x00000010
+#endif /* PCMREC_PARANOID */
+/** Errors **/
+/* failed to load encoder */
+#define PCMREC_E_LOAD_ENCODER           0x80001000
+/* error originating in encoder */
+#define PCMREC_E_ENCODER                0x80002000
+/* filename queue has desynced from stream markers */
+#define PCMREC_E_FNQ_DESYNC             0x80004000
+#ifdef PCMREC_PARANOID
+/* encoder has written past end of allotted space */
+#define PCMREC_E_CHUNK_OVF              0x80008000
+/* chunk header incorrect */
+#define PCMREC_E_BAD_CHUNK              0x80010000
+/* encoder read position changed outside of recording control */
+#define PCMREC_E_ENC_RD_INDEX_TRASHED   0x80020000
+/* encoder write position changed outside of recording control */
+#define PCMREC_E_ENC_WR_INDEX_TRASHED   0x80040000
+#endif /* PCMREC_PARANOID */
+
 /**
  * RAW pcm data recording
  * These calls are nescessary only when using the raw pcm apis directly.
@@ -54,6 +85,7 @@ void pcm_rec_error_clear(void);
 /* pcm_rec_status is deprecated for general use. audio_status merges the
    results for consistency with the hardware codec version */
 unsigned long pcm_rec_status(void);
+unsigned long pcm_rec_get_warnings(void);
 void pcm_rec_init(void);
 int  pcm_rec_current_bitrate(void);
 int  pcm_rec_encoder_afmt(void); /* AFMT_* value, AFMT_UNKNOWN if none */
diff --git a/firmware/pcm_record.c b/firmware/pcm_record.c
index 93a6e067b1..34b104d29a 100644
--- a/firmware/pcm_record.c
+++ b/firmware/pcm_record.c
@@ -60,10 +60,11 @@ volatile pcm_more_callback_type2 pcm_callback_more_ready = NULL;
 volatile bool                    pcm_recording           = false;
 
 /** General recording state **/
-static bool is_recording;              /* We are recording */
-static bool is_paused;                 /* We have paused   */
-static bool is_stopping;                 /* We are currently stopping      */
-static bool is_error;                  /* An error has occured */
+static bool is_recording;              /* We are recording                 */
+static bool is_paused;                 /* We have paused                   */
+static bool is_stopping;               /* We are currently stopping        */
+static unsigned long errors;           /* An error has occured             */
+static unsigned long warnings;         /* Warning                          */
 
 /** Stats on encoded data for current file **/
 static size_t        num_rec_bytes;      /* Num bytes recorded             */
@@ -91,6 +92,7 @@ static int           rec_frequency;      /* current frequency setting      */
 static unsigned long sample_rate;        /* Sample rate in HZ              */
 static int           num_channels;       /* Current number of channels     */
 static struct encoder_config enc_config; /* Current encoder configuration  */
+static unsigned long  pre_record_ticks;  /* pre-record time in ticks       */
   
 /****************************************************************************
   use 2 circular buffers:
@@ -104,16 +106,24 @@ static struct encoder_config enc_config; /* Current encoder configuration  */
   3. pcmrec_callback detects enc_buffer 'near full' and writes data to disk
 
   Functions calls (basic encoder steps):
-  1.main:    audio_load_encoder();   start the encoder
-  2.encoder: enc_get_inputs();       get encoder recording settings
-  3.encoder: enc_set_parameters();   set the encoder parameters
-  4.encoder: enc_get_pcm_data();     get n bytes of unprocessed pcm data
-  5.encoder: enc_pcm_buf_near_empty(); if 1: reduce cpu_boost
-  6.encoder: enc_alloc_chunk();      get a ptr to next enc chunk
-  7.encoder: <process enc chunk>     compress and store data to enc chunk
-  8.encoder: enc_free_chunk();       inform main about chunk process finished
-  9.encoder: repeat 4. to 8.
-  A.pcmrec:  enc_events_callback();   called for certain events
+  1.main:    audio_load_encoder();     start the encoder
+  2.encoder: enc_get_inputs();         get encoder recording settings
+  3.encoder: enc_set_parameters();     set the encoder parameters
+  4.encoder: enc_get_pcm_data();       get n bytes of unprocessed pcm data
+  5.encoder: enc_unget_pcm_data();     put n bytes of data back (optional)
+  6.encoder: enc_pcm_buf_near_empty(); if !0: reduce cpu_boost
+  7.encoder: enc_get_chunk();          get a ptr to next enc chunk
+  8.encoder: <process enc chunk>       compress and store data to enc chunk
+  9.encoder: enc_finish_chunk();       inform main about chunk processed and
+                                       is available to be written to a file.
+                                       Encoder can place any number of chunks
+                                       of PCM data in a single output chunk
+                                       but must stay within its output chunk
+                                       size
+  A.encoder: repeat 4. to 9.
+  B.pcmrec:  enc_events_callback();   called for certain events
+
+  (*) Optional step
 ****************************************************************************/
 
 /** buffer parameters where incoming PCM data is placed **/
@@ -124,10 +134,53 @@ static struct encoder_config enc_config; /* Current encoder configuration  */
 #define GET_PCM_CHUNK(offset)   ((long *)(pcm_buffer + (offset)))
 #define GET_ENC_CHUNK(index)    ENC_CHUNK_HDR(enc_buffer + enc_chunk_size*(index))
 
+#ifdef PCMREC_PARANOID
+static void paranoid_set_code(unsigned long code, int line)
+{
+    logf("%08X at %d", code, line);
+    if ((long)code < 0)
+        errors |= code;
+    else
+        warnings |= code;
+}
+
+#define PARANOID_ENC_INDEX_CHECK(index) \
+            { if (index != index##_last) \
+                paranoid_set_code((&index == &enc_rd_index) ? \
+                    PCMREC_E_ENC_RD_INDEX_TRASHED : PCMREC_E_ENC_WR_INDEX_TRASHED, \
+                    __LINE__); }
+#define PARANOID_PCM_POS_CHECK(pos) \
+            { if (pos != pos##_last) \
+                paranoid_set_code((&pos == &pcm_rd_pos) ? \
+                    PCMREC_W_PCM_RD_POS_TRASHED : PCMREC_W_DMA_WR_POS_TRASHED, \
+                    __LINE__); }
+#define PARANOID_SET_LAST(var) \
+            ; var##_last = var
+#define PARANOID_CHUNK_CHECK(chunk) \
+            paranoid_chunk_check(chunk)
+#else
+#define PARANOID_ENC_INDEX_CHECK(index)
+#define PARANOID_PCM_POS_CHECK(pos)
+#define PARANOID_SET_LAST(var)
+#define PARANOID_CHUNK_CHECK(chunk)
+#endif
+
 #define INC_ENC_INDEX(index) \
-            { if (++index >= enc_num_chunks) index = 0; }
+            PARANOID_ENC_INDEX_CHECK(index) \
+            { if (++index >= enc_num_chunks) index = 0; } \
+            PARANOID_SET_LAST(index)
 #define DEC_ENC_INDEX(index) \
-            { if (--index < 0) index = enc_num_chunks - 1; }
+            PARANOID_ENC_INDEX_CHECK(index) \
+            { if (--index < 0) index = enc_num_chunks - 1; } \
+            PARANOID_SET_LAST(index)
+#define SET_ENC_INDEX(index, value) \
+            PARANOID_ENC_INDEX_CHECK(index) \
+            index = value \
+            PARANOID_SET_LAST(index)
+#define SET_PCM_POS(pos, value) \
+            PARANOID_PCM_POS_CHECK(pos) \
+            pos = value \
+            PARANOID_SET_LAST(pos)
 
 static size_t         rec_buffer_size; /* size of available buffer         */
 static unsigned char *pcm_buffer;      /* circular recording buffer        */
@@ -135,14 +188,12 @@ static unsigned char *enc_buffer;      /* circular encoding buffer         */
 static volatile int   dma_wr_pos;      /* current DMA write pos            */
 static int            pcm_rd_pos;      /* current PCM read pos             */
 static volatile bool  dma_lock;        /* lock DMA write position          */
-static unsigned long  pre_record_ticks;/* pre-record time in ticks         */
 static int            enc_wr_index;    /* encoder chunk write index        */
 static int            enc_rd_index;    /* encoder chunk read index         */
-static int            enc_num_chunks;  /* number of chunks in ringbuffer     */
+static int            enc_num_chunks;  /* number of chunks in ringbuffer   */
 static size_t         enc_chunk_size;  /* maximum encoder chunk size       */
-static size_t         enc_data_size;   /* maximum data size for encoder    */
 static unsigned long  enc_sample_rate; /* sample rate used by encoder      */
-static bool           wav_queue_empty; /* all wav chunks processed?          */
+static bool           wav_queue_empty; /* all wav chunks processed?        */
  
 /** file flushing **/
 static int            write_threshold; /* max chunk limit for data flush   */
@@ -159,6 +210,16 @@ static ssize_t        fnq_size;        /* capacity of queue in bytes       */
 static int            fnq_rd_pos;      /* current read position            */
 static int            fnq_wr_pos;      /* current write position           */
 
+/** extra debugging info positioned away from other vars **/
+#ifdef PCMREC_PARANOID
+static unsigned long *wrap_id_p;       /* magic at end of encoding buffer  */
+static volatile int   dma_wr_pos_last; /* previous dma write position      */ 
+static int            pcm_rd_pos_last; /* previous pcm read position       */
+static int            enc_rd_index_last; /* previsou encoder read position */
+static int            enc_wr_index_last; /* previsou encoder read position */
+#endif
+
+
 /***************************************************************************/
 
 static struct event_queue  pcmrec_queue;
@@ -169,19 +230,18 @@ static void pcmrec_thread(void);
 
 /* Event values which are also single-bit flags */
 #define PCMREC_INIT         0x00000001  /* enable recording                */
-#define PCMREC_CLOSE        0x00000002
-
-#define PCMREC_START        0x00000004  /* start recording (when stopped)  */
-#define PCMREC_STOP         0x00000008  /* stop the current recording      */
-#define PCMREC_PAUSE        0x00000010  /* pause the current recording     */
-#define PCMREC_RESUME       0x00000020  /* resume the current recording    */
-#define PCMREC_NEW_FILE     0x00000040  /* start new file (when recording) */
-#define PCMREC_SET_GAIN     0x00000080
+#define PCMREC_CLOSE        0x00000002  /* close recording                 */
+#define PCMREC_OPTIONS      0x00000004  /* set recording options           */
+#define PCMREC_START        0x00000008  /* start recording                 */
+#define PCMREC_STOP         0x00000010  /* stop the current recording      */
+#define PCMREC_PAUSE        0x00000020  /* pause the current recording     */
+#define PCMREC_RESUME       0x00000040  /* resume the current recording    */
+#define PCMREC_NEW_FILE     0x00000080  /* start new file                  */
 #define PCMREC_FLUSH_NUM    0x00000100  /* flush a number of files out     */
 #define PCMREC_FINISH_STOP  0x00000200  /* finish the stopping recording   */
 
 /* mask for signaling events */
-static volatile long pcm_thread_event_mask;
+static volatile long pcm_thread_event_mask = PCMREC_CLOSE;
 
 static void pcm_thread_sync_post(long event, void *data)
 {
@@ -206,21 +266,11 @@ static inline bool pcm_thread_event_state(long signaled, long unsignaled)
     return ((signaled | unsignaled) & pcm_thread_event_mask) == signaled;
 } /* pcm_thread_event_state */
  
-static void pcm_thread_wait_for_stop(void)
-{
-    if (is_stopping)
-    {
-        logf("waiting for stop to finish");
-        while (is_stopping)
-            yield();
-    }
-} /* pcm_thread_wait_for_stop */
-
 /*******************************************************************/
 /* Functions that are not executing in the pcmrec_thread first     */
 /*******************************************************************/
     
-/* Callback for when more data is ready */
+/* Callback for when more data is ready - called in interrupt context */
 static int pcm_rec_have_more(int status)
 {
     if (status < 0)
@@ -237,7 +287,23 @@ static int pcm_rec_have_more(int status)
     else if (!dma_lock)
     {
         /* advance write position */
-        dma_wr_pos = (dma_wr_pos + PCM_CHUNK_SIZE) & PCM_CHUNK_MASK;
+        int next_pos = (dma_wr_pos + PCM_CHUNK_SIZE) & PCM_CHUNK_MASK;
+
+        /* set pcm ovf if read position is inside current write chunk */
+        if ((unsigned)(pcm_rd_pos - next_pos) < PCM_CHUNK_SIZE)
+            warnings |= PCMREC_W_PCM_BUFFER_OVF;
+
+#ifdef PCMREC_PARANOID
+        /* write position must always be on PCM_CHUNK_SIZE boundary -
+           anything else is corruption */
+        if (next_pos & (PCM_CHUNK_SIZE-1))
+        {
+            logf("dma_wr_pos unalgn: %d", next_pos);
+            warnings |= PCMREC_W_DMA_WR_POS_ALIGN;
+            next_pos &= ~PCM_CHUNK_SIZE; /* re-align */
+        }
+#endif
+        SET_PCM_POS(dma_wr_pos, next_pos);
     }
 
     pcm_record_more(GET_PCM_CHUNK(dma_wr_pos), PCM_CHUNK_SIZE);
@@ -253,31 +319,47 @@ static void reset_hardware(void)
 }
 
 /** pcm_rec_* group **/
+
+/**
+ * Clear all errors and warnings
+ */
 void pcm_rec_error_clear(void)
 {
-    is_error = false;
+    errors = warnings = 0;
 } /* pcm_rec_error_clear */
 
+/**
+ * Check mode, errors and warnings
+ */
 unsigned long pcm_rec_status(void)
 {
     unsigned long ret = 0;
 
     if (is_recording)
         ret |= AUDIO_STATUS_RECORD;
+    else if (pre_record_ticks)
+        ret |= AUDIO_STATUS_PRERECORD;
 
     if (is_paused)
         ret |= AUDIO_STATUS_PAUSE;
 
-    if (is_error)
+    if (errors)
         ret |= AUDIO_STATUS_ERROR;
 
-    if (!is_recording && pre_record_ticks &&
-        pcm_thread_event_state(PCMREC_INIT, PCMREC_CLOSE))
-        ret |= AUDIO_STATUS_PRERECORD;
+    if (warnings)
+        ret |= AUDIO_STATUS_WARNING;
 
     return ret;
 } /* pcm_rec_status */
 
+/**
+ * Return warnings that have occured since recording started
+ */
+unsigned long pcm_rec_get_warnings(void)
+{
+    return warnings;
+}
+
 #if 0
 int pcm_rec_current_bitrate(void)
 {
@@ -325,171 +407,133 @@ void pcm_rec_init(void)
 
 /** audio_* group **/
 
+/* NOTE: The following posting functions are really only single-thread safe
+         at the moment since a response to a particular message at a particular
+         position in the queue can't be distinguished */
+
+/**
+ * Initializes recording - call before calling any other recording function
+ */
 void audio_init_recording(unsigned int buffer_offset)
 {
-    (void)buffer_offset;
-    pcm_thread_wait_for_stop();
+    logf("audio_init_recording");
     pcm_thread_sync_post(PCMREC_INIT, NULL);
+    logf("audio_init_recording done");
+    (void)buffer_offset;
 } /* audio_init_recording */
 
+/**
+ * Closes recording - call audio_stop_recording first
+ */
 void audio_close_recording(void)
 {
-    pcm_thread_wait_for_stop();
+    logf("audio_close_recording");
     pcm_thread_sync_post(PCMREC_CLOSE, NULL);
-    reset_hardware();
-    audio_remove_encoder();
+    logf("audio_close_recording done");
 } /* audio_close_recording */
 
-unsigned long audio_recorded_time(void)
-{
-    if (!is_recording || enc_sample_rate == 0)
-        return 0;
-
-    /* return actual recorded time a la encoded data even if encoder rate
-       doesn't match the pcm rate */
-    return (long)(HZ*(unsigned long long)num_rec_samples / enc_sample_rate);
-} /* audio_recorded_time */
-
-unsigned long audio_num_recorded_bytes(void)
-{
-    if (!is_recording)
-        return 0;
-
-    return num_rec_bytes;
-} /* audio_num_recorded_bytes */
-    
-#ifdef HAVE_SPDIF_IN
-/**
- * Return SPDIF sample rate index in audio_master_sampr_list. Since we base
- * our reading on the actual SPDIF sample rate (which might be a bit
- * inaccurate), we round off to the closest sample rate that is supported by
- * SPDIF.
- */
-int audio_get_spdif_sample_rate(void)
-{
-    unsigned long measured_rate = spdif_measure_frequency();
-    /* Find which SPDIF sample rate we're closest to. */
-    return round_value_to_list32(measured_rate, audio_master_sampr_list,
-                                 SAMPR_NUM_FREQ, false);
-} /* audio_get_spdif_sample_rate */
-#endif /* HAVE_SPDIF_IN */
-
 /**
  * Sets recording parameters
  */
 void audio_set_recording_options(struct audio_recording_options *options)
 {
-    pcm_thread_wait_for_stop();
-
-    /* stop DMA transfer */
-    dma_lock = true;
-    pcm_stop_recording();
-
-    rec_frequency      = options->rec_frequency;
-    rec_source         = options->rec_source;
-    num_channels       = options->rec_channels == 1 ? 1 : 2;
-    pre_record_ticks   = options->rec_prerecord_time * HZ;
-    enc_config         = options->enc_config;
-    enc_config.afmt    = rec_format_afmt[enc_config.rec_format];
-
-#ifdef HAVE_SPDIF_IN
-    if (rec_source == AUDIO_SRC_SPDIF)
-    {
-        /* must measure SPDIF sample rate before configuring codecs */
-        unsigned long sr = spdif_measure_frequency();
-        /* round to master list for SPDIF rate */
-        int index = round_value_to_list32(sr, audio_master_sampr_list,
-                                          SAMPR_NUM_FREQ, false);
-        sample_rate = audio_master_sampr_list[index];
-        /* round to HW playback rates for monitoring */
-        index = round_value_to_list32(sr, hw_freq_sampr,
-                                      HW_NUM_FREQ, false);
-        pcm_set_frequency(hw_freq_sampr[index]);
-        /* encoders with a limited number of rates do their own rounding */
-    }
-    else
-#endif
-    {
-        /* set sample rate from frequency selection */
-        sample_rate = rec_freq_sampr[rec_frequency];
-        pcm_set_frequency(sample_rate);
-    }
-
-    /* set monitoring */
-    audio_set_output_source(rec_source);
-
-    /* apply pcm settings to hardware */
-    pcm_apply_settings(true);
-
-    if (audio_load_encoder(enc_config.afmt))
-    {
-        /* start DMA transfer */
-        dma_lock = pre_record_ticks == 0;
-        pcm_record_data(pcm_rec_have_more, GET_PCM_CHUNK(dma_wr_pos),
-                        PCM_CHUNK_SIZE);
-    }
-    else
-    {
-        logf("set rec opt: enc load failed");
-        is_error = true;
-    }
+    logf("audio_set_recording_options");
+    pcm_thread_sync_post(PCMREC_OPTIONS, (void *)options);
+    logf("audio_set_recording_options done");
 } /* audio_set_recording_options */
 
 /**
- * Start recording
- * 
- * Use audio_set_recording_options first to select recording options
+ * Start recording if not recording or else split
  */
 void audio_record(const char *filename)
 {
     logf("audio_record: %s", filename);
-
-    pcm_thread_wait_for_stop();
     pcm_thread_sync_post(PCMREC_START, (void *)filename);
-
     logf("audio_record_done");
 } /* audio_record */
 
+/**
+ * Equivalent to audio_record()
+ */
 void audio_new_file(const char *filename)
 {
     logf("audio_new_file: %s", filename);
-
-    pcm_thread_wait_for_stop();
     pcm_thread_sync_post(PCMREC_NEW_FILE, (void *)filename);
-
     logf("audio_new_file done");
 } /* audio_new_file */
 
+/**
+ * Stop current recording if recording
+ */
 void audio_stop_recording(void)
 {
     logf("audio_stop_recording");
-
-    pcm_thread_wait_for_stop();
     pcm_thread_sync_post(PCMREC_STOP, NULL);
-
     logf("audio_stop_recording done");
 } /* audio_stop_recording */
 
+/**
+ * Pause current recording
+ */
 void audio_pause_recording(void)
 {
     logf("audio_pause_recording");
-    
-    pcm_thread_wait_for_stop();
     pcm_thread_sync_post(PCMREC_PAUSE, NULL);
-
     logf("audio_pause_recording done");
 } /* audio_pause_recording */
-    
+
+/**
+ * Resume current recording if paused
+ */    
 void audio_resume_recording(void)
 {
     logf("audio_resume_recording");
-
-    pcm_thread_wait_for_stop();
     pcm_thread_sync_post(PCMREC_RESUME, NULL);
-
     logf("audio_resume_recording done");
 } /* audio_resume_recording */
 
+/** Information about current state **/
+
+/**
+ * Return current recorded time in ticks (playback eqivalent time)
+ */
+unsigned long audio_recorded_time(void)
+{
+    if (!is_recording || enc_sample_rate == 0)
+        return 0;
+
+    /* return actual recorded time a la encoded data even if encoder rate
+       doesn't match the pcm rate */
+    return (long)(HZ*(unsigned long long)num_rec_samples / enc_sample_rate);
+} /* audio_recorded_time */
+
+/**
+ * Return number of bytes encoded to output
+ */
+unsigned long audio_num_recorded_bytes(void)
+{
+    if (!is_recording)
+        return 0;
+
+    return num_rec_bytes;
+} /* audio_num_recorded_bytes */
+    
+#ifdef HAVE_SPDIF_IN
+/**
+ * Return SPDIF sample rate index in audio_master_sampr_list. Since we base
+ * our reading on the actual SPDIF sample rate (which might be a bit
+ * inaccurate), we round off to the closest sample rate that is supported by
+ * SPDIF.
+ */
+int audio_get_spdif_sample_rate(void)
+{
+    unsigned long measured_rate = spdif_measure_frequency();
+    /* Find which SPDIF sample rate we're closest to. */
+    return round_value_to_list32(measured_rate, audio_master_sampr_list,
+                                 SAMPR_NUM_FREQ, false);
+} /* audio_get_spdif_sample_rate */
+#endif /* HAVE_SPDIF_IN */
+
 /***************************************************************************/
 /*                                                                         */
 /*         Functions that execute in the context of pcmrec_thread          */
@@ -580,6 +624,51 @@ static void pcmrec_close_file(int *fd_p)
     *fd_p = -1;
 } /* pcmrec_close_file */
 
+#ifdef PCMREC_PARANOID
+static void paranoid_chunk_check(const struct enc_chunk_hdr *chunk)
+{
+    /* check integrity of things that must be ok - data or not */
+
+    /* check magic in header */
+    if (chunk->id != ENC_CHUNK_MAGIC)
+    {
+        errors |= PCMREC_E_BAD_CHUNK | PCMREC_E_CHUNK_OVF;
+        logf("bad chunk: %d", chunk - (struct enc_chunk_hdr *)enc_buffer);
+    }
+
+    /* check magic wrap id */
+    if (*wrap_id_p != ENC_CHUNK_MAGIC)
+    {
+        errors |= PCMREC_E_BAD_CHUNK | PCMREC_E_CHUNK_OVF;
+        logf("bad magic at wrap pos");
+    }
+
+    if (chunk->enc_data == NULL) /* has data? */
+        return;
+
+    /* check that data points to something after header */
+    if (chunk->enc_data < ENC_CHUNK_SKIP_HDR(chunk->enc_data, chunk))
+    {
+        errors |= PCMREC_E_BAD_CHUNK;
+        logf("chk ptr < hdr end");
+    }
+
+        /* check if data end is within chunk */
+    if (chunk->enc_data + chunk->enc_size >
+            (unsigned char *)chunk + enc_chunk_size)
+    {
+        errors |= PCMREC_E_BAD_CHUNK;
+        logf("chk data > chk end");
+    }
+
+    if ((chunk->flags & ~CHUNKF_ALLFLAGS) != 0)
+    {
+        errors |= PCMREC_E_BAD_CHUNK;
+        logf("chk bad flags %08X", chunk->flags);
+    }
+} /* paranoid_chunk_check */
+#endif /* PCMREC_PARANOID */
+
 /** Data Flushing **/
 
 /**
@@ -627,20 +716,20 @@ static void pcmrec_start_file(void)
     {
         logf("start file: fnq empty");
         *filename = '\0';
-        is_error = true;
+        errors |= PCMREC_E_FNQ_DESYNC;
     }
-    else if (is_error)
+    else if (errors != 0)
     {
-        logf("start file: is_error already");
+        logf("start file: error already");
     }
     else if (curr_rec_file >= 0)
     {
         /* Any previous file should have been closed */
         logf("start file: file already open");
-        is_error = true;
+        errors |= PCMREC_E_FNQ_DESYNC;
     }
     
-    if (is_error)
+    if (errors != 0)
         rec_fdata.chunk->flags |= CHUNKF_ERROR;
 
     /* encoder can set error flag here and should increase
@@ -649,13 +738,13 @@ static void pcmrec_start_file(void)
     rec_fdata.filename = filename;
     enc_events_callback(ENC_START_FILE, &rec_fdata);
 
-    if (!is_error && (rec_fdata.chunk->flags & CHUNKF_ERROR))
+    if (errors == 0 && (rec_fdata.chunk->flags & CHUNKF_ERROR))
     {
         logf("start file: enc error");
-        is_error = true;
+        errors |= PCMREC_E_ENCODER;
     }
 
-    if (is_error)
+    if (errors != 0)
     {
         pcmrec_close_file(&curr_rec_file);
         /* Write no more to this file */
@@ -674,7 +763,7 @@ static inline void pcmrec_write_chunk(void)
     size_t        enc_size = rec_fdata.new_enc_size;
     unsigned long num_pcm  = rec_fdata.new_num_pcm;
 
-    if (is_error)
+    if (errors != 0)
         rec_fdata.chunk->flags |= CHUNKF_ERROR;
 
     enc_events_callback(ENC_WRITE_CHUNK, &rec_fdata);
@@ -683,11 +772,11 @@ static inline void pcmrec_write_chunk(void)
     {
         pcmrec_update_sizes_inl(enc_size, num_pcm);
     }
-    else if (!is_error)
+    else if (errors == 0)
     {
         logf("wr chk enc error %d %d",
              rec_fdata.chunk->enc_size, rec_fdata.chunk->num_pcm);
-        is_error = true;
+        errors |= PCMREC_E_ENCODER;
     }
 } /* pcmrec_write_chunk */
 
@@ -701,12 +790,12 @@ static void pcmrec_end_file(void)
 
     enc_events_callback(ENC_END_FILE, &rec_fdata);
 
-    if (!is_error)
+    if (errors == 0)
     {
         if (rec_fdata.chunk->flags & CHUNKF_ERROR)
         {
             logf("end file: enc error");
-            is_error = true;
+            errors |= PCMREC_E_ENCODER;
         }
         else
         {
@@ -715,7 +804,7 @@ static void pcmrec_end_file(void)
     }
 
     /* Force file close if error */
-    if (is_error)
+    if (errors != 0)
         pcmrec_close_file(&rec_fdata.rec_file);
 
     rec_fdata.chunk->flags &= ~CHUNKF_END_FILE;
@@ -792,7 +881,7 @@ static void pcmrec_flush(unsigned flush_num)
         
     cpu_boost(true);
 
-    for (i=0; i<num_ready; i++)
+    for (i = 0; i < num_ready; i++)
     {
         if (prio == -1 && (num >= panic_threshold ||
                            current_tick - start_tick > 10*HZ))
@@ -806,6 +895,8 @@ static void pcmrec_flush(unsigned flush_num)
         rec_fdata.new_enc_size = rec_fdata.chunk->enc_size;
         rec_fdata.new_num_pcm  = rec_fdata.chunk->num_pcm;
 
+        PARANOID_CHUNK_CHECK(rec_fdata.chunk);
+
         if (rec_fdata.chunk->flags & CHUNKF_START_FILE)
         {
             pcmrec_start_file();
@@ -821,7 +912,7 @@ static void pcmrec_flush(unsigned flush_num)
 
         INC_ENC_INDEX(enc_rd_index);
 
-        if (is_error)
+        if (errors != 0)
             break;
 
         if (prio == -1)
@@ -877,6 +968,9 @@ static void pcmrec_new_stream(const char *filename, /* next file name */
 
     struct enc_chunk_hdr * get_prev_chunk(int index)
     {
+#ifdef PCMREC_PARANOID
+        int index_last = index;
+#endif
         DEC_ENC_INDEX(index);
         return GET_ENC_CHUNK(index);
     }
@@ -947,8 +1041,8 @@ static void pcmrec_new_stream(const char *filename, /* next file name */
         }
         else
         {
-                logf("adding filename: %s", filename);
-                fnq_add_fn = pcmrec_fnq_add_filename;
+            logf("adding filename: %s", filename);
+            fnq_add_fn = pcmrec_fnq_add_filename;
         }
     }
 
@@ -967,6 +1061,9 @@ static void pcmrec_new_stream(const char *filename, /* next file name */
         {
             /* get stats on data added to start - sort of a prerecord operation */
             int i = get_chunk_index(data.chunk);
+#ifdef PCMREC_PARANOID
+            int i_last = i;
+#endif
             struct enc_chunk_hdr *chunk = data.chunk;
 
             logf("start data: %d %d", i, enc_wr_index);
@@ -1008,14 +1105,18 @@ static void pcmrec_init(void)
 
     rec_fdata.rec_file = -1;
 
+    /* warings and errors */
+    warnings          =
+    errors            = 0;
+
     /* pcm FIFO */
     dma_lock          = true;
-    pcm_rd_pos        = 0;
-    dma_wr_pos        = 0;
+    SET_PCM_POS(pcm_rd_pos, 0);
+    SET_PCM_POS(dma_wr_pos, 0);
 
     /* encoder FIFO */
-    enc_wr_index      = 0;
-    enc_rd_index      = 0;
+    SET_ENC_INDEX(enc_wr_index, 0);
+    SET_ENC_INDEX(enc_rd_index, 0);
 
     /* filename queue */
     fnq_rd_pos        = 0;
@@ -1029,11 +1130,11 @@ static void pcmrec_init(void)
     accum_pcm_samples = 0;
 #endif
 
-    pcm_thread_unsignal_event(PCMREC_CLOSE);
+    pre_record_ticks  = 0;
+
     is_recording      = false;
     is_paused         = false;
     is_stopping       = false;
-    is_error          = false;
 
     buffer = audio_get_recording_buffer(&rec_buffer_size);
     /* Line align pcm_buffer 2^4=16 bytes */
@@ -1044,6 +1145,7 @@ static void pcmrec_init(void)
     rec_buffer_size -= pcm_buffer - buffer;
 
     pcm_init_recording();
+    pcm_thread_unsignal_event(PCMREC_CLOSE);
     pcm_thread_signal_event(PCMREC_INIT);
 } /* pcmrec_init */
 
@@ -1051,41 +1153,113 @@ static void pcmrec_init(void)
 static void pcmrec_close(void)
 {
     dma_lock = true;
+    pre_record_ticks = 0; /* Can't be prerecording any more */
+    warnings         = 0;
     pcm_close_recording();
+    reset_hardware();
+    audio_remove_encoder();
     pcm_thread_unsignal_event(PCMREC_INIT);
     pcm_thread_signal_event(PCMREC_CLOSE);
 } /* pcmrec_close */
 
-/* PCMREC_START */
-static void pcmrec_start(const char *filename)
+/* PCMREC_OPTIONS */
+static void pcmrec_set_recording_options(struct audio_recording_options *options)
+{
+    /* stop DMA transfer */
+    dma_lock = true;
+    pcm_stop_recording();
+
+    rec_frequency      = options->rec_frequency;
+    rec_source         = options->rec_source;
+    num_channels       = options->rec_channels == 1 ? 1 : 2;
+    pre_record_ticks   = options->rec_prerecord_time * HZ;
+    enc_config         = options->enc_config;
+    enc_config.afmt    = rec_format_afmt[enc_config.rec_format];
+
+#ifdef HAVE_SPDIF_IN
+    if (rec_source == AUDIO_SRC_SPDIF)
+    {
+        /* must measure SPDIF sample rate before configuring codecs */
+        unsigned long sr = spdif_measure_frequency();
+        /* round to master list for SPDIF rate */
+        int index = round_value_to_list32(sr, audio_master_sampr_list,
+                                          SAMPR_NUM_FREQ, false);
+        sample_rate = audio_master_sampr_list[index];
+        /* round to HW playback rates for monitoring */
+        index = round_value_to_list32(sr, hw_freq_sampr,
+                                      HW_NUM_FREQ, false);
+        pcm_set_frequency(hw_freq_sampr[index]);
+        /* encoders with a limited number of rates do their own rounding */
+    }
+    else
+#endif
+    {
+        /* set sample rate from frequency selection */
+        sample_rate = rec_freq_sampr[rec_frequency];
+        pcm_set_frequency(sample_rate);
+    }
+
+    /* set monitoring */
+    audio_set_output_source(rec_source);
+
+    /* apply pcm settings to hardware */
+    pcm_apply_settings(true);
+
+    if (audio_load_encoder(enc_config.afmt))
+    {
+        /* start DMA transfer */
+        dma_lock = pre_record_ticks == 0;
+        pcm_record_data(pcm_rec_have_more, GET_PCM_CHUNK(dma_wr_pos),
+                        PCM_CHUNK_SIZE);
+    }
+    else
+    {
+        logf("set rec opt: enc load failed");
+        errors |= PCMREC_E_LOAD_ENCODER;
+    }
+
+    pcm_thread_signal_event(PCMREC_OPTIONS);
+} /* pcmrec_set_recording_options */
+
+/* PCMREC_START/PCMREC_NEW_FILE - start recording (not gapless)
+                                  or split stream (gapless) */
+static void pcmrec_start(int event, const char *filename)
 {
     unsigned long pre_sample_ticks;
     int           rd_start;
 
     logf("pcmrec_start: %s", filename);
 
+    /* reset stats */
+    num_rec_bytes     = 0;
+    num_rec_samples   = 0;
+
     if (is_recording) 
     {
-        logf("already recording");
-        goto already_recording;
+        /* already recording, just split the stream */
+        logf("inserting split");
+        pcmrec_new_stream(filename,
+                          CHUNKF_START_FILE | CHUNKF_END_FILE,
+                          0);
+        goto start_done;
     }
 
-    /* reset stats */
-    num_rec_bytes     = 0;
-    num_rec_samples   = 0;
 #if 0
     accum_rec_bytes   = 0;
     accum_pcm_samples = 0;
 #endif
     spinup_time       = -1;
+    warnings          = 0; /* reset warnings */
 
     rd_start  = enc_wr_index;
     pre_sample_ticks = 0;
 
     if (pre_record_ticks)
     {
-        int i;
-
+        int i = rd_start;
+#ifdef PCMREC_PARANOID
+        int i_last = i;
+#endif
         /* calculate number of available chunks */
         unsigned long avail_pre_chunks = (enc_wr_index - enc_rd_index +
                         enc_num_chunks) % enc_num_chunks;
@@ -1094,7 +1268,7 @@ static void pcmrec_start(const char *filename)
 
         /* Get exact measure of recorded data as number of samples aren't
            nescessarily going to be the max for each chunk */
-        for (i = rd_start; avail_pre_chunks-- > 0;)
+        for (; avail_pre_chunks-- > 0;)
         {
             struct enc_chunk_hdr *chunk;
             unsigned long chunk_sample_ticks;
@@ -1125,7 +1299,7 @@ static void pcmrec_start(const char *filename)
 #endif
     }
 
-    enc_rd_index = rd_start;
+    SET_ENC_INDEX(enc_rd_index, rd_start);
 
     /* filename queue should be empty */
     if (!pcmrec_fnq_is_empty())
@@ -1143,8 +1317,8 @@ static void pcmrec_start(const char *filename)
                       (pre_sample_ticks > 0 ? CHUNKF_PRERECORD : 0),
                       enc_rd_index);
 
-already_recording:
-    pcm_thread_signal_event(PCMREC_START);
+start_done:
+    pcm_thread_signal_event(event);
     logf("pcmrec_start done");
 } /* pcmrec_start */
 
@@ -1189,7 +1363,7 @@ static void pcmrec_finish_stop(void)
     pcmrec_flush(-1);
     
     /* wait for encoder to finish remaining data */
-    while (!is_error && !wav_queue_empty)
+    while (errors == 0 && !wav_queue_empty)
         yield();
     
     /* end stream at last data */
@@ -1212,7 +1386,7 @@ static void pcmrec_finish_stop(void)
     }   
 
     /* be absolutely sure the file is closed */
-    if (is_error)
+    if (errors != 0)
         pcmrec_close_file(&rec_fdata.rec_file);
     rec_fdata.rec_file = -1;
 
@@ -1265,7 +1439,7 @@ static void pcmrec_resume(void)
         goto not_recording_or_not_paused;
     }
     
-    is_paused = false;
+    is_paused    = false;
     is_recording = true;
     dma_lock     = false;
     
@@ -1274,29 +1448,6 @@ not_recording_or_not_paused:
     logf("pcmrec_resume done");
 } /* pcmrec_resume */
 
-/* PCMREC_NEW_FILE */
-static void pcmrec_new_file(const char *filename)
-{
-    logf("pcmrec_new_file: %s", filename);
-
-    if (!is_recording)
-    {
-        logf("not recording");
-        goto not_recording;
-    }
-    
-    num_rec_bytes = 0;
-    num_rec_samples = 0;
-
-    pcmrec_new_stream(filename,
-                      CHUNKF_START_FILE | CHUNKF_END_FILE,
-                      0);
-
-not_recording:
-    pcm_thread_signal_event(PCMREC_NEW_FILE);
-    logf("pcmrec_new_file done");
-} /* pcmrec_new_file */
-
 static void pcmrec_thread(void) __attribute__((noreturn));
 static void pcmrec_thread(void)
 {
@@ -1325,7 +1476,7 @@ static void pcmrec_thread(void)
 
         switch (ev.id)
         {
-            case PCMREC_INIT: 
+            case PCMREC_INIT:
                 pcmrec_init();
                 break;
 
@@ -1333,8 +1484,14 @@ static void pcmrec_thread(void)
                 pcmrec_close();
                 break;
 
+            case PCMREC_OPTIONS:
+                pcmrec_set_recording_options(
+                    (struct audio_recording_options *)ev.data);
+                break;
+
             case PCMREC_START:
-                pcmrec_start((const char *)ev.data);
+            case PCMREC_NEW_FILE:
+                pcmrec_start(ev.id, (const char *)ev.data);
                 break;
 
             case PCMREC_STOP:
@@ -1353,10 +1510,6 @@ static void pcmrec_thread(void)
                 pcmrec_resume();
                 break;
 
-            case PCMREC_NEW_FILE:
-                pcmrec_new_file((const char *)ev.data);
-                break;
-
             case PCMREC_FLUSH_NUM:
                 pcmrec_flush((unsigned)ev.data);
                 break;
@@ -1407,13 +1560,12 @@ void enc_set_parameters(struct enc_parameters *params)
     enc_sample_rate = params->enc_sample_rate;
     logf("enc sampr:%d", enc_sample_rate);
 
-    pcm_rd_pos = dma_wr_pos;
+    SET_PCM_POS(pcm_rd_pos, dma_wr_pos);
 
     enc_config.afmt     = params->afmt;
     /* addition of the header is always implied - chunk size 4-byte aligned */
     enc_chunk_size      =
                 ALIGN_UP_P2(ENC_CHUNK_HDR_SIZE + params->chunk_size, 2);
-    enc_data_size       = enc_chunk_size - ENC_CHUNK_HDR_SIZE;
     enc_events_callback = params->events_callback;
 
     logf("chunk size:%d", enc_chunk_size);
@@ -1430,7 +1582,11 @@ void enc_set_parameters(struct enc_parameters *params)
     logf("resbytes:%d", resbytes);
 
     bufsize   = rec_buffer_size - (enc_buffer - pcm_buffer) -
-                resbytes - FNQ_MIN_NUM_PATHS*MAX_PATH;
+                resbytes - FNQ_MIN_NUM_PATHS*MAX_PATH
+#ifdef PCMREC_PARANOID
+                - sizeof (*wrap_id_p)
+#endif
+                ;
 
     enc_num_chunks = bufsize / enc_chunk_size;
     logf("num chunks:%d", enc_num_chunks);
@@ -1439,6 +1595,13 @@ void enc_set_parameters(struct enc_parameters *params)
     bufsize = enc_num_chunks*enc_chunk_size;
     logf("enc size:%d", bufsize);
 
+#ifdef PCMREC_PARANOID
+    /* add magic at wraparound */
+    wrap_id_p  = SKIPBYTES((unsigned long *)enc_buffer, bufsize);
+    bufsize   += sizeof (*wrap_id_p);
+    *wrap_id_p = ENC_CHUNK_MAGIC;
+#endif /* PCMREC_PARANOID */
+
     /* panic boost thread priority at 1 second remaining */
     panic_threshold = enc_num_chunks -
                       (4*sample_rate + (enc_chunk_size-1)) / enc_chunk_size;
@@ -1473,15 +1636,24 @@ void enc_set_parameters(struct enc_parameters *params)
     logf("pcm:%08X", (unsigned long)pcm_buffer);
     logf("enc:%08X", (unsigned long)enc_buffer);
     logf("res:%08X", (unsigned long)params->reserve_buffer);
+#ifdef PCMREC_PARANOID
+    logf("wip:%08X", (unsigned long)wrap_id_p);
+#endif
     logf("fnq:%08X", (unsigned long)fn_queue);
     logf("end:%08X", (unsigned long)fn_queue + fnq_size);
     logf("abe:%08X", (unsigned long)audiobufend);
 #endif
 
     /* init all chunk headers and reset indexes */
-    enc_rd_index = 0;
+    SET_ENC_INDEX(enc_rd_index, 0);
     for (enc_wr_index = enc_num_chunks; enc_wr_index > 0; )
-        GET_ENC_CHUNK(--enc_wr_index)->flags = 0;
+    {
+        struct enc_chunk_hdr *chunk = GET_ENC_CHUNK(--enc_wr_index);
+#ifdef PCMREC_PARANOID
+        chunk->id    = ENC_CHUNK_MAGIC;
+#endif
+        chunk->flags = 0;
+    }
 
     logf("enc_set_parameters done");
 } /* enc_set_parameters */
@@ -1490,6 +1662,15 @@ void enc_set_parameters(struct enc_parameters *params)
 struct enc_chunk_hdr * enc_get_chunk(void)
 {
     struct enc_chunk_hdr *chunk = GET_ENC_CHUNK(enc_wr_index);
+
+#ifdef PCMREC_PARANOID
+    if (chunk->id != ENC_CHUNK_MAGIC || *wrap_id_p != ENC_CHUNK_MAGIC)
+    {
+        errors |= PCMREC_E_CHUNK_OVF;
+        logf("finish chk ovf: %d", enc_wr_index);
+    }
+#endif
+
     chunk->flags &= CHUNKF_START_FILE;
 
     if (!is_recording)
@@ -1503,42 +1684,31 @@ void enc_finish_chunk(void)
 {
     struct enc_chunk_hdr *chunk = GET_ENC_CHUNK(enc_wr_index);
 
-    /* encoder may have set error flag or written too much data */
-    if ((long)chunk->flags < 0 || chunk->enc_size > enc_data_size)
+    if ((long)chunk->flags < 0)
     {
-        is_error = true;
-
-#ifdef ROCKBOX_HAS_LOGF
-        if (chunk->enc_size > enc_data_size)
-        {
-            /* illegal to scribble over next chunk */
-            logf("finish chk ovf: %d>%d", chunk->enc_size, enc_data_size);
-        }
-        else
-        {
-            /* encoder set error flag */
-            logf("finish chk enc error");
-        }
-#endif
+        /* encoder set error flag */
+        errors |= PCMREC_E_ENCODER;
+        logf("finish chk enc error");
     }
 
+    PARANOID_CHUNK_CHECK(chunk);
+
     /* advance enc_wr_index to the next encoder chunk */
     INC_ENC_INDEX(enc_wr_index);
 
     if (enc_rd_index != enc_wr_index)
     {
         num_rec_bytes      += chunk->enc_size;
-#if 0
-        accum_rec_bytes    += chunk->enc_size;
-#endif
         num_rec_samples    += chunk->num_pcm;
 #if 0
+        accum_rec_bytes    += chunk->enc_size;
         accum_pcm_samples  += chunk->num_pcm;
 #endif
     }
     else if (is_recording)        /* buffer full */
     {
-        /* keep current position */
+        /* keep current position - but put up warning flag */
+        warnings |= PCMREC_W_ENC_BUFFER_OVF;
         logf("enc_buffer ovf");
         DEC_ENC_INDEX(enc_wr_index);
     }
@@ -1572,7 +1742,10 @@ unsigned char * enc_get_pcm_data(size_t size)
     if (avail >= size)
     {
         unsigned char *ptr = pcm_buffer + pcm_rd_pos;
-        pcm_rd_pos = (pcm_rd_pos + size) & PCM_CHUNK_MASK;
+        int next_pos = (pcm_rd_pos + size) & PCM_CHUNK_MASK;
+
+        SET_PCM_POS(pcm_rd_pos, next_pos);
+        pcm_rd_pos = next_pos;
 
         /* ptr must point to continous data at wraparound position */
         if ((size_t)pcm_rd_pos < size)
@@ -1599,12 +1772,14 @@ size_t enc_unget_pcm_data(size_t size)
         /* disallow backing up into current DMA write chunk  */
         size_t old_avail = (pcm_rd_pos - dma_wr_pos - PCM_CHUNK_SIZE)
                             & PCM_CHUNK_MASK;
+        int next_pos;
 
         /* limit size to amount of old data remaining */
         if (size > old_avail)
             size = old_avail;
 
-        pcm_rd_pos = (pcm_rd_pos - size) & PCM_CHUNK_MASK;
+        next_pos = (pcm_rd_pos - size) & PCM_CHUNK_MASK;
+        SET_PCM_POS(pcm_rd_pos, next_pos);
     }
 
     set_irq_level(level);