Module Name: src
Committed By: nia
Date: Fri Oct 16 12:36:01 UTC 2020
Modified Files:
src/lib/libossaudio: ossaudio.c
Log Message:
ossaudio: Add comments for the more obscure parts of SNDCTL_AUDIOINFO
To generate a diff of this commit:
cvs rdiff -u -r1.45 -r1.46 src/lib/libossaudio/ossaudio.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libossaudio/ossaudio.c
diff -u src/lib/libossaudio/ossaudio.c:1.45 src/lib/libossaudio/ossaudio.c:1.46
--- src/lib/libossaudio/ossaudio.c:1.45 Fri Oct 16 12:23:34 2020
+++ src/lib/libossaudio/ossaudio.c Fri Oct 16 12:36:01 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: ossaudio.c,v 1.45 2020/10/16 12:23:34 nia Exp $ */
+/* $NetBSD: ossaudio.c,v 1.46 2020/10/16 12:36:01 nia Exp $ */
/*-
* Copyright (c) 1997 The NetBSD Foundation, Inc.
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: ossaudio.c,v 1.45 2020/10/16 12:23:34 nia Exp $");
+__RCSID("$NetBSD: ossaudio.c,v 1.46 2020/10/16 12:36:01 nia Exp $");
/*
* This is an OSS (Linux) sound API emulator.
@@ -574,6 +574,15 @@ audio_ioctl(int fd, unsigned long com, v
tmpaudioinfo = (struct oss_audioinfo*)argp;
if (tmpaudioinfo == NULL)
return EINVAL;
+
+ /*
+ * Takes the audio dev node as input, since this ioctl is
+ * supposed to work on the OSS /dev/mixer to query all
+ * all available audio devices.
+ *
+ * If the input device is -1, guess the device related to
+ * the open mixer device.
+ */
if (tmpaudioinfo->dev < 0) {
fstat(fd, &tmpstat);
if ((tmpstat.st_rdev & 0xff00) == 0x2a00)
@@ -619,7 +628,7 @@ audio_ioctl(int fd, unsigned long com, v
tmpaudioinfo->caps = idat;
ioctl(newfd, SNDCTL_DSP_GETFMTS, &tmpaudioinfo->iformats);
tmpaudioinfo->oformats = tmpaudioinfo->iformats;
- tmpaudioinfo->magic = -1;
+ tmpaudioinfo->magic = -1; /* reserved for "internal use" */
memset(tmpaudioinfo->cmd, 0, sizeof(tmpaudioinfo->cmd));
tmpaudioinfo->card_number = -1;
memset(tmpaudioinfo->song_name, 0,
@@ -627,10 +636,10 @@ audio_ioctl(int fd, unsigned long com, v
memset(tmpaudioinfo->label, 0, sizeof(tmpaudioinfo->label));
tmpaudioinfo->port_number = 0;
tmpaudioinfo->mixer_dev = tmpaudioinfo->dev;
- tmpaudioinfo->legacy_device = -1;
+ tmpaudioinfo->legacy_device = tmpaudioinfo->dev;
tmpaudioinfo->enabled = 1;
- tmpaudioinfo->flags = -1;
- tmpaudioinfo->min_rate = 8000;
+ tmpaudioinfo->flags = -1; /* reserved for "future versions" */
+ tmpaudioinfo->min_rate = 1000;
tmpaudioinfo->max_rate = 192000;
tmpaudioinfo->nrates = 0;
tmpaudioinfo->min_channels = 1;
@@ -639,8 +648,12 @@ audio_ioctl(int fd, unsigned long com, v
if (fmtq.fmt.channels > (unsigned)tmpaudioinfo->max_channels)
tmpaudioinfo->max_channels = fmtq.fmt.channels;
}
- tmpaudioinfo->binding = -1;
+ tmpaudioinfo->binding = -1; /* reserved for "future versions" */
tmpaudioinfo->rate_source = -1;
+ /*
+ * 'handle' is supposed to be globally unique. The closest
+ * we have to that is probably device nodes.
+ */
strlcpy(tmpaudioinfo->handle, tmpaudioinfo->devnode,
sizeof(tmpaudioinfo->handle));
tmpaudioinfo->next_play_engine = 0;
