当AudioRecorder应用程序暂停时，gstreamer alsa源仍会打开PCM。
我试图打电话做准备，当状态为PLAYING_TO_PAUSED时关闭。
gst_alsasrc_change_state（）
。 。
GST_STATE_CHANGE_PLAYING_TO_PAUSED案例：
gst_alsasrc_unprepare(alsa); gst_alsasrc_close(alsa);。 。
但是gstreamer仍然像下面这样调用snd_pcm_readi（）
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi：alsalib错误：PCM未设置 /gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery：xrun恢复-5：未知错误-5 /alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi：alsalib错误：PCM未设置 /gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery：xrun恢复-5：未知错误-5 /alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi：alsalib错误：PCM未设置 /gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery：xrun恢复-5：未知错误-5 /alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi：alsalib错误：PCM未设置 /gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery：xrun恢复-5：未知错误-5
gstalsasrc.c暂停时如何释放PCM？
这是日志
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:1102:gst_alsasrc_read: gst_alsasrc_read()
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:1102:gst_alsasrc_read: gst_alsasrc_read()
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:251:gst_alsasrc_change_state: GST_STATE_CHANGE_PLAYING_TO_PAUSED
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:258:gst_alsasrc_change_state: call unprepare
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:917:gst_alsasrc_unprepare: gst_alsasrc_unprepare()
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:933:gst_alsasrc_unprepare: gst_alsasrc_unprepare() done
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:261:gst_alsasrc_change_state: call close
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
systemd[1]: app-logic-voicerecorder.service: main process exited, code=killed, status=6/ABRT
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery: xrun recovery -5: Unknown error -5
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
. . .
systemd[1]: Unit app-logic-voicerecorder.service entered failed state.
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery: xrun recovery -5: Unknown error -5
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery: xrun recovery -5: Unknown error -5
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:941:gst_alsasrc_close: gst_alsasrc_close()
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:957:gst_alsasrc_close: gst_alsasrc_close() call snd_pcm_close()
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery: xrun recovery -5: Unknown error -5
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery: xrun recovery -5: Unknown error -5
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery: xrun recovery -5: Unknown error -5
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery: xrun recovery -5: Unknown error -5
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:977:gst_alsasrc_close: gst_alsasrc_close() done
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:263:gst_alsasrc_change_state: set isPCMOpened = FALSE
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1318:snd_pcm_readi: alsalib error: PCM not set up
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:990: snd_pcm_delay: Assertion pcm' failed.
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:988:xrun_recovery:<alsasrc0> xrun recovery -5: Unknown error -5
/alsa-lib/1.0.29-r0/alsa-lib-1.0.29/src/pcm/pcm.c:1315: snd_pcm_readi: Assertionpcm' failed.
start-stop-daemon[831]: No /usr/bin/app-logic-voicerecorder found running; none killed.
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsaplugin.c:71:plugin_init: binding text domain gst-plugins-base-1.0 to locale dir /usr/share/locale
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsaplugin.c:71:plugin_init: binding text domain gst-plugins-base-1.0 to locale dir /usr/share/locale
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasink.c:357:gst_alsasink_init: gst_alsasink_init()
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:361:gst_alsasrc_init: gst_alsasrc_init
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:382:gst_alsasrc_getcaps: gst_alsasrc_getcaps
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:386:gst_alsasrc_getcaps: device not open, using template caps
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:382:gst_alsasrc_getcaps: gst_alsasrc_getcaps
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:386:gst_alsasrc_getcaps: device not open, using template caps
/gstreamer1.0-plugins-base/1.2.4-r0/git/ext/alsa/gstalsasrc.c:191:gst_alsasrc_set_property: gst_alsasrc_set_property