[newlib-cygwin] Cygwin: dsp: Fix SNDCTL_DSP_{POST,SYNC} ioctl() behaviour.

[Takashi Yano <tyan0@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=0ab22f0af975e114003ec6bfa5d72f66f5999c44

commit 0ab22f0af975e114003ec6bfa5d72f66f5999c44
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Sat Feb 25 10:28:34 2023 +0900

    Cygwin: dsp: Fix SNDCTL_DSP_{POST,SYNC} ioctl() behaviour.
    
    Previously, SNDCTL_DSP_POST and SNDCTL_DSP_SYNC were implemented
    wrongly. Due to this issue, module-oss of pulseaudio generates
    choppy sound when SNDCTL_DSP_POST is called. This patch fixes that.
    
    Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

Diff:
---
 winsup/cygwin/fhandler/dsp.cc | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/winsup/cygwin/fhandler/dsp.cc b/winsup/cygwin/fhandler/dsp.cc
index 16db6bb29..27f0a50ce 100644
--- a/winsup/cygwin/fhandler/dsp.cc
+++ b/winsup/cygwin/fhandler/dsp.cc
@@ -133,6 +133,8 @@ class fhandler_dev_dsp::Audio_out: public Audio
   int freq_;
   int bits_;
   int channels_;
+
+  friend fhandler_dev_dsp;
 };
 
 static void CALLBACK waveIn_callback (HWAVEIN hWave, UINT msg,
@@ -1429,11 +1431,16 @@ fhandler_dev_dsp::_ioctl (unsigned int cmd, void *buf)
 	return 0;
 
       CASE (SNDCTL_DSP_POST)
+	if (audio_out_)
+	  audio_out_->sendcurrent (); // force out last block whatever size..
+	return 0;
+
       CASE (SNDCTL_DSP_SYNC)
-	// Stop audio out device
-	close_audio_out ();
-	// Stop audio in device
-	close_audio_in ();
+	if (audio_out_)
+	  {
+	    audio_out_->sendcurrent (); // force out last block whatever size..
+	    audio_out_->waitforallsent (); // block till finished..
+	  }
 	return 0;
 
     default: