Cygwin: dsp: Avoid setting buffer that is too small.

The buffer size that is too small causes choppy sound. That is not
practical at all. With this patch, the minimum value of the buffer
size (i.e. fragstotal * fragsize) is restricted to 16384 bytes.

Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

winsup/cygwin/fhandler/dsp.cc

@@ -1430,6 +1430,8 @@ fhandler_dev_dsp::_ioctl (unsigned int cmd, void *buf)
 	int *p = (int *) buf;
 	fragstotal_ = min (*p >> 16, MAX_BLOCKS);
 	fragsize_ = 1 << (*p & 0xffff);
+	while (fragsize_ * fragstotal_ < 16384)
+	  fragsize_ *= 2;
 	fragment_has_been_set = true;
 	return 0;
       }