pcm: handle negative values from snd_pcm_mmap_hw_avail

Such negative values can happen when an underrun happens and xrun
detection is disabled. Another situation is if the device updated the
pointer before alsa-lib has a chance to detect the xrun.

The problem is that these negative values could propagate to the
snd_pcm_rewindable return value, where it is specified that negative
returns must be interpreted as error codes and not as negative amount of
samples.

Signed-off-by: Alexander E. Patrakov <patrakov@gmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/pcm/pcm_dmix.c b/src/pcm/pcm_dmix.c
index ffde12a1a46cd3177c5f1e31320da7d7992d30d8..babde6a15efe34762e95b023639282f8a99ab7e0 100644 (file)
--- a/src/pcm/pcm_dmix.c
+++ b/src/pcm/pcm_dmix.c
@@ -661,7 +661,7 @@ static int snd_pcm_dmix_pause(snd_pcm_t *pcm ATTRIBUTE_UNUSED, int enable ATTRIB
 
 static snd_pcm_sframes_t snd_pcm_dmix_rewindable(snd_pcm_t *pcm)
 {
-       return snd_pcm_mmap_hw_avail(pcm);
+       return snd_pcm_mmap_playback_hw_rewindable(pcm);
 }
 
 static snd_pcm_sframes_t snd_pcm_dmix_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

diff --git a/src/pcm/pcm_dshare.c b/src/pcm/pcm_dshare.c
index f1a1a1d7522916abc5cc6b7f84c8f84b9e9fbcc0..020e6f7d930732a107ab6bc0f8c351e24111c658 100644 (file)
--- a/src/pcm/pcm_dshare.c
+++ b/src/pcm/pcm_dshare.c
@@ -412,7 +412,7 @@ static int snd_pcm_dshare_pause(snd_pcm_t *pcm ATTRIBUTE_UNUSED, int enable ATTR
 
 static snd_pcm_sframes_t snd_pcm_dshare_rewindable(snd_pcm_t *pcm)
 {
-       return snd_pcm_mmap_playback_hw_avail(pcm);
+       return snd_pcm_mmap_playback_hw_rewindable(pcm);
 }
 
 static snd_pcm_sframes_t snd_pcm_dshare_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
@@ -420,8 +420,6 @@ static snd_pcm_sframes_t snd_pcm_dshare_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t
        snd_pcm_sframes_t avail;
 
        avail = snd_pcm_dshare_rewindable(pcm);
-       if (avail < 0)
-               return 0;
        if (frames > (snd_pcm_uframes_t)avail)
                frames = avail;
        snd_pcm_mmap_appl_backward(pcm, frames);

diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c
index 74cff672a0c11fe5702af3c575a36480eefd94f6..c34b766ee0353969d9096f0d51fe8246f2e843d0 100644 (file)
--- a/src/pcm/pcm_hw.c
+++ b/src/pcm/pcm_hw.c
@@ -659,7 +659,7 @@ static int snd_pcm_hw_pause(snd_pcm_t *pcm, int enable)
 
 static snd_pcm_sframes_t snd_pcm_hw_rewindable(snd_pcm_t *pcm)
 {
-       return snd_pcm_mmap_hw_avail(pcm);
+       return snd_pcm_mmap_hw_rewindable(pcm);
 }
 
 static snd_pcm_sframes_t snd_pcm_hw_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

diff --git a/src/pcm/pcm_ioplug.c b/src/pcm/pcm_ioplug.c
index 85a88911eafc7ef7b64d0ccf8cdb8cf5a793d615..fe9347c835d54afd51f226d965828b7db9a6c39c 100644 (file)
--- a/src/pcm/pcm_ioplug.c
+++ b/src/pcm/pcm_ioplug.c
@@ -503,7 +503,7 @@ static int snd_pcm_ioplug_pause(snd_pcm_t *pcm, int enable)
 
 static snd_pcm_sframes_t snd_pcm_ioplug_rewindable(snd_pcm_t *pcm)
 {
-       return snd_pcm_mmap_hw_avail(pcm);
+       return snd_pcm_mmap_hw_rewindable(pcm);
 }
 
 static snd_pcm_sframes_t snd_pcm_ioplug_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

diff --git a/src/pcm/pcm_local.h b/src/pcm/pcm_local.h
index 74ebd609334a57d31e36466ddf611386291a3cb4..394505f978ace3b2de052c4d3102f473c543577e 100644 (file)
--- a/src/pcm/pcm_local.h
+++ b/src/pcm/pcm_local.h
@@ -464,6 +464,24 @@ static inline snd_pcm_sframes_t snd_pcm_mmap_hw_avail(snd_pcm_t *pcm)
        return pcm->buffer_size - snd_pcm_mmap_avail(pcm);
 }
 
+static inline snd_pcm_sframes_t snd_pcm_mmap_playback_hw_rewindable(snd_pcm_t *pcm)
+{
+       snd_pcm_sframes_t ret = snd_pcm_mmap_playback_hw_avail(pcm);
+       return (ret >= 0) ? ret : 0;
+}
+
+static inline snd_pcm_sframes_t snd_pcm_mmap_capture_hw_rewindable(snd_pcm_t *pcm)
+{
+       snd_pcm_sframes_t ret = snd_pcm_mmap_capture_hw_avail(pcm);
+       return (ret >= 0) ? ret : 0;
+}
+
+static inline snd_pcm_uframes_t snd_pcm_mmap_hw_rewindable(snd_pcm_t *pcm)
+{
+       snd_pcm_sframes_t ret = snd_pcm_mmap_hw_avail(pcm);
+       return (ret >= 0) ? ret : 0;
+}
+
 static inline const snd_pcm_channel_area_t *snd_pcm_mmap_areas(snd_pcm_t *pcm)
 {
        if (pcm->stopped_areas &&

diff --git a/src/pcm/pcm_plugin.c b/src/pcm/pcm_plugin.c
index a607ccfe27de437743824c0fec19016aff340fda..c19e2f17a730c8912c9fecbb5e4d2a63359eb6b9 100644 (file)
--- a/src/pcm/pcm_plugin.c
+++ b/src/pcm/pcm_plugin.c
@@ -198,7 +198,7 @@ static int snd_pcm_plugin_reset(snd_pcm_t *pcm)
 
 static snd_pcm_sframes_t snd_pcm_plugin_rewindable(snd_pcm_t *pcm)
 {
-       return snd_pcm_mmap_hw_avail(pcm);
+       return snd_pcm_mmap_hw_rewindable(pcm);
 }
 
 snd_pcm_sframes_t snd_pcm_plugin_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)