<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=gb2312"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style></style></head><body lang=ZH-CN link=blue vlink=purple style='text-justify-trim:punctuation'><div class=WordSection1>Hi<o:p></o:p>>> I was using autaudiosink and appsrc as my sink and src. A usb earphone<o:p></o:p>>> was used as output device. The problem was: when I detected the<o:p></o:p>>> plugging out of the usb earphone, I called gst_element_set_state(pipe,<o:p></o:p>>> GST_STATE_NULL). Then the function blocked and did not return.<o:p></o:p><o:p> </o:p>>That sounds like a bug somewhere. Could be in GStreamer, or in the<o:p></o:p>>drivers.<o:p></o:p>><o:p> </o:p>>Maybe connect to the process with gdb to see where the different threads<o:p></o:p>>are stuck.<o:p></o:p><o:p> </o:p>With gdb，I found these two interesting stacks:<o:p></o:p>(gdb) t 1<o:p></o:p>[Switching to thread 1 (Thread 3524.0xde8)]<o:p></o:p>#0 0x7c92e4f4 in ntdll!KiFastSystemCallRet () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>(gdb) bt<o:p></o:p>#0 0x7c92e4f4 in ntdll!KiFastSystemCallRet () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#1 0x7c92df3c in ntdll!ZwWaitForSingleObject () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#2 0x7c93b22b in ntdll!RtlpWaitForCriticalSection () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#3 0x7c921046 in ntdll!RtlEnterCriticalSection () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#4 0x0000eec8 in ?? ()<o:p></o:p>#5 0x686317ab in g_thread_xp_AcquireSRWLockExclusive (mutex=0xa2b3e50) at gthread-win32.c:635<o:p></o:p>#6 0x686318b0 in g_mutex_lock (mutex=0xa2b3e50) at gthread-win32.c:140<o:p></o:p>#7 0x67541baa in gst_directsound_sink_reset (asink=0xa2b3c08) at gstdirectsoundsink.c:673<o:p></o:p>#8 0x64bad0dc in _fu572___gst_debug_min () at gstaudiosink.c:534<o:p></o:p>#9 0x64b84900 in _fu25___gst_debug_min () at gstaudioringbuffer.c:998<o:p></o:p>#10 0x64b878d7 in _fu87___gst_debug_min () at gstaudioringbuffer.c:1041<o:p></o:p>#11 0x64ba7a7c in gst_audio_base_sink_change_state (element=0xa2b3c08, transition=GST_STATE_CHANGE_PLAYING_TO_PAUSED) at gstaudiobasesink.c:2232<o:p></o:p>#12 0x6146af97 in gst_element_change_state (element=element@entry=0xa2b3c08, transition=transition@entry=GST_STATE_CHANGE_PLAYING_TO_PAUSED) at gstelement.c:2599<o:p></o:p>#13 0x6146b5e0 in gst_element_set_state_func (element=0xa2b3c08, state=GST_STATE_PAUSED) at gstelement.c:2555<o:p></o:p>#14 0x6144decb in gst_bin_element_set_state (next=GST_STATE_PAUSED, current=GST_STATE_PLAYING, start_time=8934011725, base_time=32862639246, element=0xa2b3c08, bin=0x6026bf0) at gstbin.c:2323<o:p></o:p>#15 gst_bin_change_state_func (element=<optimized out>, transition=GST_STATE_CHANGE_PLAYING_TO_PAUSED) at gstbin.c:2660<o:p></o:p>#16 0x63f8254b in _fu10___gst_debug_min () at gstautodetect.c:416<o:p></o:p>#17 0x6146af97 in gst_element_change_state (element=element@entry=0x6026bf0, transition=transition@entry=GST_STATE_CHANGE_PLAYING_TO_PAUSED) at gstelement.c:2599<o:p></o:p>#18 0x6146b5e0 in gst_element_set_state_func (element=0x6026bf0, state=GST_STATE_PAUSED) at gstelement.c:2555<o:p></o:p>#19 0x6144decb in gst_bin_element_set_state (next=GST_STATE_PAUSED, current=GST_STATE_PLAYING, start_time=8934011725, base_time=32862639246, element=0x6026bf0, bin=0x1bb9458) at gstbin.c:2323<o:p></o:p>#20 gst_bin_change_state_func (element=<optimized out>, transition=GST_STATE_CHANGE_PLAYING_TO_PAUSED) at gstbin.c:2660<o:p></o:p>#21 0x6148b564 in gst_pipeline_change_state (element=0x1bb9458, transition=GST_STATE_CHANGE_PLAYING_TO_PAUSED) at gstpipeline.c:469<o:p></o:p>#22 0x6146af97 in gst_element_change_state (element=element@entry=0x1bb9458, transition=transition@entry=GST_STATE_CHANGE_PLAYING_TO_PAUSED) at gstelement.c:2599<o:p></o:p>#23 0x6146b5e0 in gst_element_set_state_func (element=0x1bb9458, state=GST_STATE_NULL) at gstelement.c:2555<o:p></o:p><o:p> </o:p>(gdb) t 12<o:p></o:p>[Switching to thread 12 (Thread 3524.0x9a4)]<o:p></o:p>#0 0x7c92e4f4 in ntdll!KiFastSystemCallRet () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>(gdb) bt<o:p></o:p>#0 0x7c92e4f4 in ntdll!KiFastSystemCallRet () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#1 0x7c92df3c in ntdll!ZwWaitForSingleObject () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#2 0x7c93b22b in ntdll!RtlpWaitForCriticalSection () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#3 0x7c921046 in ntdll!RtlEnterCriticalSection () from C:\WINDOWS\system32\ntdll.dll<o:p></o:p>#4 0x001e3ea0 in ?? ()<o:p></o:p>#5 0x686317ab in g_thread_xp_AcquireSRWLockExclusive (mutex=0x61e3b7c) at gthread-win32.c:635<o:p></o:p>#6 0x686318b0 in g_mutex_lock (mutex=mutex@entry=0x61e3b7c) at gthread-win32.c:140<o:p></o:p>#7 0x6863199b in g_thread_xp_SleepConditionVariableSRW (cond=0x61e3bb0, mutex=0x61e3b7c, timeout=4294967295, flags=0) at gthread-win32.c:856<o:p></o:p>#8 0x68631cc8 in g_cond_wait (cond=0x61e3bb0, entered_mutex=0x61e3b7c) at gthread-win32.c:302<o:p></o:p>#9 0x64b8666a in _fu70___gst_debug_min () at gstaudioringbuffer.c:1305<o:p></o:p>#10 0x64b868d1 in _fu72___gst_debug_min () at gstaudioringbuffer.c:1532<o:p></o:p>#11 0x64ba1b03 in _fu435___gst_debug_min () at gstaudiobasesink.c:1930<o:p></o:p>#12 0x6b5dfcae in _fu433___gst_debug_min () at gstbasesink.c:3424<o:p></o:p>#13 0x6b5e1a9b in _fu445___gst_debug_min () at gstbasesink.c:3532<o:p></o:p>#14 0x61480ca4 in gst_pad_chain_data_unchecked (data=0x602ca40, type=4112, pad=0x5fc82b8) at gstpad.c:3820<o:p></o:p>#15 gst_pad_push_data (pad=0x1bb8640, type=4112, data=<optimized out>) at gstpad.c:4053<o:p></o:p>#16 0x6147110e in gst_proxy_pad_chain_default (pad=0x60271a0, parent=0x6026bf0, buffer=0x602ca40) at gstghostpad.c:126<o:p></o:p>#17 0x61480ca4 in gst_pad_chain_data_unchecked (data=0x602ca40, type=4112, pad=0x60271a0) at gstpad.c:3820<o:p></o:p>#18 gst_pad_push_data (pad=0x6026d30, type=4112, data=<optimized out>) at gstpad.c:4053<o:p></o:p>#19 0x6b5f0dc2 in gst_base_transform_chain (pad=0x60266c8, parent=0x62407b0, buffer=0x602ca40) at gstbasetransform.c:2261<o:p></o:p>#20 0x61480ca4 in gst_pad_chain_data_unchecked (data=0x602ca40, type=4112, pad=0x60266c8) at gstpad.c:3820<o:p></o:p>#21 gst_pad_push_data (pad=0x60262f0, type=4112, data=<optimized out>) at gstpad.c:4053<o:p></o:p>#22 0x6b5f0dc2 in gst_base_transform_chain (pad=0x6026810, parent=0xaf2f830, buffer=0x602cae0) at gstbasetransform.c:2261<o:p></o:p>#23 0x61480ca4 in gst_pad_chain_data_unchecked (data=0x602cae0, type=4112, pad=0x6026810) at gstpad.c:3820<o:p></o:p>#24 gst_pad_push_data (pad=0x6026438, type=4112, data=<optimized out>) at gstpad.c:4053<o:p></o:p>#25 0x6e0a08e4 in gst_queue_push_one (queue=0x6011378) at gstqueue.c:1118<o:p></o:p>#26 _fu680___gst_buffer_type () at gstqueue.c:1247<o:p></o:p>#27 0x614af828 in gst_task_func (task=0x5fd0230) at gsttask.c:317<o:p></o:p>#28 0x68616bc7 in g_thread_pool_thread_proxy (data=0x1c0b370) at gthreadpool.c:309<o:p></o:p>#29 0x686162ad in g_thread_proxy (data=0x5ffb510) at gthread.c:798<o:p></o:p>#30 0x68631ecd in g_thread_win32_proxy (data=0x5ffb510) at gthread-win32.c:452<o:p></o:p>#31 0x77c0a3b0 in msvcrt!_endthreadex () from C:\WINDOWS\system32\msvcrt.dll<o:p></o:p>#32 0x7c80b713 in KERNEL32!GetModuleFileNameA () from C:\WINDOWS\system32\kernel32.dll<o:p></o:p>#33 0x00000000 in ?? ()<o:p></o:p>(gdb)<o:p></o:p><o:p> </o:p>>What version of GStreamer is this with? I remember there being an issue<o:p></o:p>>with 0.10 when usb sound devices were disconnected, and I fixed some<o:p></o:p>>issues in 1.x.<o:p></o:p>I used 0.10 before. Following your advice, I upgraded gstreamer to 1.3.2. But the problem hadn’t been solved.<o:p></o:p>The gdb stack was captured with 1.3.2 version. <o:p></o:p><o:p> </o:p>Thanks!<o:p></o:p>--<o:p></o:p>Yongjian<o:p></o:p><o:p> </o:p></div></body></html>