GopherProxy

	tUse a callback to read mixer volume - spoon - dwm status utility (2f30 fork)
	git clone git://src.adamsgaard.dk/spoon
	Log
	Files
	Refs
	LICENSE
	---
	commit f66774791e87bf8bbebacf7f7c0511af1c7a2298
	parent 4981b3a67901a712d52ab9a921cf571232de88c1
	Author: lostd <[email protected]>
	Date: Wed, 16 Nov 2016 15:07:02 +0000

	Use a callback to read mixer volume

	Reduces CPU usage quite a lot.

	Diffstat:
	M mix.c \| 64 ++++++++++++++++++++++-------…

	1 file changed, 46 insertions(+), 18 deletions(-)
	---
	diff --git a/mix.c b/mix.c
	t@@ -1,6 +1,8 @@
	#include <err.h>
	#include <stdio.h>

	+#include "util.h"
	+
	#ifdef __OpenBSD__
	#include <sys/ioctl.h>
	#include <sys/audioio.h>
	t@@ -66,15 +68,46 @@ out:
	#elif __linux__
	#include <alsa/asoundlib.h>

	+static int master;
	+
	+int
	+mixer_elem_cb(snd_mixer_elem_t *elem, unsigned int mask)
	+{
	+ long min, max, vol;
	+ int r;
	+
	+ r = snd_mixer_selem_get_playback_volume_range(elem, &min, &max);
	+ if (r < 0) {
	+ warnx("snd_mixer_selem_get_playback_volume_range: %s",
	+ snd_strerror(r));
	+ return -1;
	+ }
	+ r = snd_mixer_selem_get_playback_volume(elem,
	+ SND_MIXER_SCHN_FRONT_LEFT, &vol);
	+ if (r < 0) {
	+ warnx("snd_mixer_selem_get_playback_volume: %s",
	+ snd_strerror(r));
	+ return -1;
	+ }
	+ /* compute percentage */
	+ vol -= min;
	+ max -= min;
	+ if (max == 0)
	+ master = 0;
	+ else
	+ master = 100 * vol / max;
	+ DPRINTF_D(master);
	+ return 0;
	+}
	+
	int
	mixread(void arg, char buf, size_t len)
	{
	snd_mixer_selem_id_t *id;
	snd_mixer_elem_t *elem;
	static snd_mixer_t *mixerp;
	- long min, max, vol;
	+ struct pollfd pfd[1];
	int r;
	- int master;

	snd_mixer_selem_id_alloca(&id);
	snd_mixer_selem_id_set_name(id, "Master");
	t@@ -98,7 +131,6 @@ mixread(void arg, char buf, size_t len)
	warnx("snd_mixer_selem_register: %s", snd_strerror(r));
	goto out;
	}
	-readvol:
	r = snd_mixer_load(mixerp);
	if (r < 0) {
	warnx("snd_mixer_load: %s", snd_strerror(r));
	t@@ -109,30 +141,26 @@ readvol:
	warnx("could not find mixer element");
	goto out;
	}
	- r = snd_mixer_selem_get_playback_volume_range(elem, &min, &max);
	+ snd_mixer_elem_set_callback(elem, mixer_elem_cb);
	+ /* force the callback the first time around */
	+ r = mixer_elem_cb(elem, 0);
	+ if (r < 0)
	+ goto out;
	+readvol:
	+ r = snd_mixer_poll_descriptors(mixerp, pfd, LEN(pfd));
	if (r < 0) {
	- warnx("snd_mixer_selem_get_playback_volume_range: %s",
	- snd_strerror(r));
	+ warnx("snd_mixer_poll_descriptors: %s", snd_strerror(r));
	goto out;
	}
	- r = snd_mixer_selem_get_playback_volume(elem,
	- SND_MIXER_SCHN_FRONT_LEFT, &vol);
	+ r = snd_mixer_handle_events(mixerp);
	if (r < 0) {
	- warnx("snd_mixer_selem_get_playback_volume: %s",
	- snd_strerror(r));
	+ warnx("snd_mixer_handle_events: %s", snd_strerror(r));
	goto out;
	}
	- /* compute percentage */
	- vol -= min;
	- max -= min;
	- if (max == 0)
	- master = 0;
	- else
	- master = 100 * vol / max;
	snprintf(buf, len, "%d%%", master);
	- snd_mixer_free(mixerp);
	return 0;
	out:
	+ snd_mixer_free(mixerp);
	snd_mixer_close(mixerp);
	mixerp = NULL;
	return -1;