spoon

set dwm status
git clone git://git.2f30.org/spoon.git
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commit f66774791e87bf8bbebacf7f7c0511af1c7a2298
parent 4981b3a67901a712d52ab9a921cf571232de88c1
Author: lostd <lostd@2f30.org>
Date:   Wed Nov 16 15:07:02 +0000

Use a callback to read mixer volume

Reduces CPU usage quite a lot.

Diffstat:
mix.c | 64++++++++++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 46 insertions(+), 18 deletions(-)
diff --git a/mix.c b/mix.c @@ -1,6 +1,8 @@ #include <err.h> #include <stdio.h> +#include "util.h" + #ifdef __OpenBSD__ #include <sys/ioctl.h> #include <sys/audioio.h> @@ -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"); @@ -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)); @@ -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;