[Spice-devel] [vdagent-linux PATCH v3 1/2] audio: add functions to set volume/mute with alsa
Victor Toso
victortoso at redhat.com
Wed Apr 1 02:55:28 PDT 2015
Hi, thanks for the review.
On Wed, Apr 01, 2015 at 11:25:12AM +0200, Christophe Fergeau wrote:
> Hey,
>
> A bunch of minor comments below
>
> On Fri, Mar 27, 2015 at 03:09:48PM +0100, Victor Toso wrote:
> > This patch includes the vdagentd-audio.[ch] files in order to
> > communicate with backend audio server.
> >
> > The two functions provide a way to set volume and mute in the guest
> > by connecting to default mixer control in alsa which is 'Master' for
> > playback and 'Capture' for record.
> > ---
> > Makefile.am | 6 +-
> > configure.ac | 1 +
> > src/vdagentd-audio.c | 168 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > src/vdagentd-audio.h | 27 +++++++++
> > 4 files changed, 200 insertions(+), 2 deletions(-)
> > create mode 100644 src/vdagentd-audio.c
> > create mode 100644 src/vdagentd-audio.h
> >
> > diff --git a/Makefile.am b/Makefile.am
> > index 510f460..d789cc1 100644
> > --- a/Makefile.am
> > +++ b/Makefile.am
> > @@ -9,11 +9,12 @@ src_spice_vdagent_LDADD = $(X_LIBS) $(SPICE_LIBS) $(GLIB2_LIBS)
> > src_spice_vdagent_SOURCES = src/vdagent.c src/vdagent-x11.c src/vdagent-x11-randr.c src/vdagent-file-xfers.c src/udscs.c
> >
> > src_spice_vdagentd_CFLAGS = $(DBUS_CFLAGS) $(LIBSYSTEMD_LOGIN_CFLAGS) \
> > - $(PCIACCESS_CFLAGS) $(SPICE_CFLAGS) $(GLIB2_CFLAGS) $(PIE_CFLAGS)
> > + $(PCIACCESS_CFLAGS) $(SPICE_CFLAGS) $(GLIB2_CFLAGS) $(PIE_CFLAGS) $(ALSA_CFLAGS)
> > src_spice_vdagentd_LDADD = $(DBUS_LIBS) $(LIBSYSTEMD_LOGIN_LIBS) \
> > - $(PCIACCESS_LIBS) $(SPICE_LIBS) $(GLIB2_LIBS) $(PIE_LDFLAGS)
> > + $(PCIACCESS_LIBS) $(SPICE_LIBS) $(GLIB2_LIBS) $(PIE_LDFLAGS) $(ALSA_LIBS)
> > src_spice_vdagentd_SOURCES = src/vdagentd.c \
> > src/vdagentd-uinput.c \
> > + src/vdagentd-audio.c \
> > src/vdagentd-xorg-conf.c \
> > src/vdagent-virtio-port.c \
> > src/udscs.c
> > @@ -37,6 +38,7 @@ noinst_HEADERS = src/glib-compat.h \
> > src/vdagentd-proto.h \
> > src/vdagentd-proto-strings.h \
> > src/vdagentd-uinput.h \
> > + src/vdagentd-audio.h \
> > src/vdagentd-xorg-conf.h
> >
> > xdgautostartdir = $(sysconfdir)/xdg/autostart
> > diff --git a/configure.ac b/configure.ac
> > index 79905a8..b011358 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -79,6 +79,7 @@ AC_ARG_ENABLE([static-uinput],
> > PKG_CHECK_MODULES([GLIB2], [glib-2.0 >= 2.12])
> > PKG_CHECK_MODULES(X, [xfixes xrandr >= 1.3 xinerama x11])
> > PKG_CHECK_MODULES(SPICE, [spice-protocol >= 0.12.5])
> > +PKG_CHECK_MODULES(ALSA, [alsa >= 1.0.22])
> >
> > if test "$with_session_info" = "auto" || test "$with_session_info" = "systemd"; then
> > PKG_CHECK_MODULES([LIBSYSTEMD_LOGIN],
> > diff --git a/src/vdagentd-audio.c b/src/vdagentd-audio.c
> > new file mode 100644
> > index 0000000..c3bfe09
> > --- /dev/null
> > +++ b/src/vdagentd-audio.c
> > @@ -0,0 +1,168 @@
> > +/* vdagentd-audio.c vdagentd audio handling code
> > +
> > + Copyright 2015 Red Hat, Inc.
> > +
> > + This program is free software: you can redistribute it and/or modify
> > + it under the terms of the GNU General Public License as published by
> > + the Free Software Foundation, either version 3 of the License, or
> > + (at your option) any later version.
> > +
> > + This program is distributed in the hope that it will be useful,
> > + but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + GNU General Public License for more details.
> > +
> > + You should have received a copy of the GNU General Public License
> > + along with this program. If not, see <http://www.gnu.org/licenses/>.
> > +*/
> > +
> > +#ifdef HAVE_CONFIG_H
> > +#include <config.h>
> > +#endif
> > +
> > +#include <glib.h>
> > +#include <syslog.h>
> > +#include <stdbool.h>
> > +#include <alsa/asoundlib.h>
> > +#include <alsa/mixer.h>
> > +#include <alsa/error.h>
> > +#include "vdagentd-audio.h"
> > +
> > +#define ALSA_MUTE 0
> > +#define ALSA_UNMUTE 1
> > +
> > +static snd_mixer_elem_t *
> > +alsa_get_default_mixer_by_name(snd_mixer_t **handle, const char *name)
>
> For what it's worth, I find it a bit weird that we use the 'alsa_'
> namespace in that file
I did not think about it mainly because alsa uses 'snd_' to its functions.
But I agree with you. I'll change to get_default_alsa_mixer_by_name(),
and the same for the other alsa_ functions.
> > +{
> > + snd_mixer_selem_id_t *sid;
> > + int err = 0;
> > +
> > + if ((err = snd_mixer_open(handle, 0)) < 0)
> > + goto fail;
> > +
> > + if ((err = snd_mixer_attach(*handle, "default")) < 0)
> > + goto fail;
> > +
> > + if ((err = snd_mixer_selem_register(*handle, NULL, NULL)) < 0)
> > + goto fail;
> > +
> > + if ((err = snd_mixer_load(*handle)) < 0)
> > + goto fail;
> > +
> > + snd_mixer_selem_id_alloca(&sid);
> > + snd_mixer_selem_id_set_index(sid, 0);
> > + snd_mixer_selem_id_set_name(sid, name);
> > + return snd_mixer_find_selem(*handle, sid);
> > +
> > +fail:
> > + syslog(LOG_WARNING, "%s fail: %s", __func__, snd_strerror(err));
> > + return NULL;
> > +}
> > +
> > +static bool alsa_set_capture(uint8_t mute, uint8_t nchannels, uint16_t *volume)
> > +{
> > + snd_mixer_t *handle = NULL;
> > + snd_mixer_elem_t *e;
> > + long min, max, vol;
> > + bool ret = true;
> > + int alsa_mute;
> > +
> > + e = alsa_get_default_mixer_by_name (&handle, "Capture");
> > + if (e == NULL) {
> > + syslog(LOG_WARNING, "vdagentd-audio: can't get default alsa mixer");
> > + ret = false;
> > + goto end;
> > + }
> > +
> > + alsa_mute = (mute) ? ALSA_MUTE : ALSA_UNMUTE;
> > + snd_mixer_selem_set_capture_switch_all(e, alsa_mute);
> > +
> > + snd_mixer_selem_get_capture_volume_range(e, &min, &max);
> > + switch (nchannels) {
> > + case 1: /* MONO */
> > + vol = CLAMP(volume[0], min, max);
> > + snd_mixer_selem_set_capture_volume(e, SND_MIXER_SCHN_MONO, vol);
> > + syslog(LOG_DEBUG, "vdagentd-audio: (capture-mono) %lu (%%%0.2f)",
> > + vol, (float) (100*vol/max));
>
> I think 100.0*vol/max would achieve the same as the (float) cast, and
> would do a float division rather than an int one, giving you something
> more accurate.
I agree. I'll fix this.
> Why %%%0.2f and not %0.2f%% ?
Just a mistake, I'll fix this as well.
(I probably thought about $ position instead of %)
>
> > + break;
> > + case 2: /* LEFT-RIGHT */
> > + vol = CLAMP(volume[0], min, max);
> > + snd_mixer_selem_set_capture_volume(e, SND_MIXER_SCHN_FRONT_LEFT, vol);
> > + syslog(LOG_DEBUG, "vdagentd-audio: (capture-left) %lu (%%%0.2f)",
> > + vol, (float) (100*vol/max));
> > + vol = CLAMP(volume[1], min, max);
> > + snd_mixer_selem_set_capture_volume(e, SND_MIXER_SCHN_FRONT_RIGHT, vol);
> > + syslog(LOG_DEBUG, "vdagentd-audio: (capture-right) %lu (%%%0.2f)",
> > + vol, (float) (100*vol/max));
> > + break;
> > + default:
> > + syslog(LOG_WARNING, "vdagentd-audio: number of channels not supported");
>
> I'd put the number of channels we got in the log.
>
> Patch looks good, even without any changes.
>
> Christophe
Thanks again,
Victor Toso
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