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ALSA: tentative hack to request audio-device.

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This commit is contained in:
Robin Gareus 2014-06-04 17:09:55 +02:00
parent 6b781f72f2
commit 40cfe86569
1 changed files with 69 additions and 0 deletions
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69
libs/backends/alsa/alsa_audiobackend.cc
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@ -28,7 +28,9 @@
#include "pbd/compose.h"
#include "pbd/error.h"
#include "pbd/file_utils.h"
#include "ardour/port_manager.h"
#include "ardour/system_exec.h"
#include "i18n.h"
using namespace ARDOUR;
@ -126,6 +128,72 @@ AlsaAudioBackend::enumerate_devices () const
return s;
}
static int card_to_num(const char* device_name)
{
char* ctl_name;
const char * comma;
snd_ctl_t* ctl_handle;
int i = -1;
if (strncasecmp(device_name, "plughw:", 7) == 0) {
device_name += 4;
}
if (!(comma = strchr(device_name, ','))) {
ctl_name = strdup(device_name);
} else {
ctl_name = strndup(device_name, comma - device_name);
}
if (snd_ctl_open (&ctl_handle, ctl_name, 0) >= 0) {
snd_ctl_card_info_t *card_info;
snd_ctl_card_info_alloca (&card_info);
if (snd_ctl_card_info(ctl_handle, card_info) >= 0) {
i = snd_ctl_card_info_get_card(card_info);
}
snd_ctl_close(ctl_handle);
}
free(ctl_name);
return i;
}
static void acquire_device(const char* device_name)
{
/* This is quick hack, ideally we'll link against libdbus and implement a dbus-listener
* that owns the device. here we try to get away by just requesting it and then block it...
* (pulseaudio periodically checks anyway)
*
* dbus-send --session --print-reply --type=method_call --dest=org.freedesktop.ReserveDevice1.Audio2 /org/freedesktop/ReserveDevice1/Audio2 org.freedesktop.ReserveDevice1.RequestRelease int32:4
* -> should not return 'boolean false'
*/
int device_number = card_to_num(device_name);
if (device_number < 0) return;
std::string dbus_send_path;
if (PBD::find_file_in_search_path (PBD::Searchpath(Glib::getenv("PATH")), X_("dbus-send"), dbus_send_path)) {
char **argp;
char tmp[128];
argp=(char**) calloc(8,sizeof(char*));
argp[0] = strdup(dbus_send_path.c_str());
argp[1] = strdup("--session");
argp[2] = strdup("--print-reply"); // need to wait for the receiver to act.
argp[3] = strdup("--type=method_call");
snprintf(tmp, sizeof(tmp), "--dest=org.freedesktop.ReserveDevice1.Audio%d", device_number);
argp[4] = strdup(tmp);
snprintf(tmp, sizeof(tmp), "/org/freedesktop/ReserveDevice1/Audio%d", device_number);
argp[5] = strdup(tmp);
argp[6] = strdup("org.freedesktop.ReserveDevice1.RequestRelease");
argp[7] = strdup("int32:4294967296");
snprintf(tmp, sizeof(tmp), "string:'org.freedesktop.ReserveDevice1.Audio%d'", device_number);
argp[7] = strdup(tmp);
argp[8] = 0;
ARDOUR::SystemExec process (dbus_send_path, argp);
if (!process.start(1)) {
process.wait();
}
}
}
std::vector<float>
AlsaAudioBackend::available_sample_rates (const std::string&) const
{
@ -436,6 +504,7 @@ AlsaAudioBackend::_start (bool for_latency_measurement)
assert(_pcmi == 0);
unsigned int pos = _capture_device.find(" ");
acquire_device(_capture_device.substr(0, pos).c_str());
_pcmi = new Alsa_pcmi (_capture_device.substr(0, pos).c_str(), _playback_device.substr(0, pos).c_str(), 0, _samplerate, _samples_per_period, _periods_per_cycle, 0);
switch (_pcmi->state ()) {
case 0: /* OK */ break;