system/pipewire
system/pipewire
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/pipewire/pipewire synced 2024-10-14 20:02:38 +00:00
Code Issues Packages Projects Releases Wiki Activity

spa: alsa: Read ctl events instead of doing a global diff

Browse source 
This does a couple of things: first, we implement revents demangling,
which seems to be required (although hw: devices work fine without it).

The second is to actually read the ctl events so we can tell when
elements we care about have changed, instead of reading everything and
trying to do a diff.

The latter is also required from a correctness perspective, as otherwise
the ctl might keep triggering wakeups while the fd is ready to be read.
This commit is contained in:
Arun Raghavan 2024-03-14 10:13:41 -04:00
parent 8a1ed01923
commit 46e6fd2ae4
2 changed files with 66 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

90
spa/plugins/alsa/alsa-pcm.c
View file

@ -674,40 +674,81 @@ static void fill_card_name(struct state *state, const char *params, char *card_n
static void bind_ctl_event(struct spa_source *source)
{
// We don't know if a bound element changed or not, so let's find out
struct state *state = source->data;
snd_ctl_event_t *ev;
snd_ctl_elem_id_t *id, *bound_id;
snd_ctl_elem_value_t *old_value;
bool changed = false;
unsigned short revents;
int err;
// Do the same demangling of revents we do for PCM pollfds
for (int i = 0; i < state->ctl_n_fds; i++) {
state->ctl_pfds[i].revents = state->ctl_sources[i].rmask;
state->ctl_sources[i].rmask = 0;
}
err = snd_ctl_poll_descriptors_revents(state->ctl, state->ctl_pfds, state->ctl_n_fds, &revents);
if (SPA_UNLIKELY(err < 0)) {
spa_log_warn(state->log, "Could not read ctl revents: %s", snd_strerror(err));
return;
}
if (!revents) {
spa_log_trace(state->log, "Got a bind ctl wakeup but no actual event");
return;
}
snd_ctl_event_alloca(&ev);
snd_ctl_elem_id_alloca(&id);
snd_ctl_elem_id_alloca(&bound_id);
snd_ctl_elem_value_alloca(&old_value);
for (unsigned int i = 0; i < state->num_bind_ctls; i++) {
int err;
while ((err = snd_ctl_read(state->ctl, ev) > 0)) {
bool changed = false;
snd_ctl_elem_value_copy(old_value, state->bound_ctls[i].value);
err = snd_ctl_elem_read(state->ctl, state->bound_ctls[i].value);
if (err < 0) {
spa_log_warn(state->log, "Could not read ctl '%s': %s",
state->bound_ctls[i].name, snd_strerror(err));
if (snd_ctl_event_get_type(ev) != SND_CTL_EVENT_ELEM)
continue;
snd_ctl_event_elem_get_id(ev, id);
for (unsigned int i = 0; i < state->num_bind_ctls; i++) {
int err;
// Check if we have the right element
snd_ctl_elem_value_get_id(state->bound_ctls[i].value, bound_id);
if (snd_ctl_elem_id_compare_set(id, bound_id) ||
snd_ctl_elem_id_compare_numid(id, bound_id)) {
continue;
}
snd_ctl_elem_value_copy(old_value, state->bound_ctls[i].value);
err = snd_ctl_elem_read(state->ctl, state->bound_ctls[i].value);
if (err < 0) {
spa_log_warn(state->log, "Could not read ctl '%s': %s",
state->bound_ctls[i].name, snd_strerror(err));
continue;
}
if (snd_ctl_elem_value_compare(old_value, state->bound_ctls[i].value) != 0) {
// We don't need to check all the ctls, if one changed,
// we'll emit a notification and they'll be read when
// the props are read
spa_log_debug(state->log, "bound ctl '%s' has changed", state->bound_ctls[i].name);
changed = true;
break;
}
}
if (snd_ctl_elem_value_compare(old_value, state->bound_ctls[i].value) != 0) {
// We don't need to check all the ctls, if one changed,
// we'll emit a notification and they'll be read when
// the props are read
spa_log_debug(state->log, "bound ctl '%s' has changed", state->bound_ctls[i].name);
changed = true;
break;
if (changed) {
state->info.change_mask |= SPA_NODE_CHANGE_MASK_PARAMS;
state->params[NODE_Props].user++;
spa_alsa_emit_node_info(state, false);
}
}
if (changed) {
state->info.change_mask |= SPA_NODE_CHANGE_MASK_PARAMS;
state->params[NODE_Props].user++;
spa_alsa_emit_node_info(state, false);
}
if (err < 0 && err != -EAGAIN)
spa_log_warn(state->log, "Could not read ctl: %s", snd_strerror(err));
}
static void fetch_bind_ctls(struct state *state)
@ -791,7 +832,6 @@ cleanup:
static void bind_ctls_for_params(struct state *state)
{
struct pollfd pfds[16];
int err;
if (state->num_bind_ctls == 0)
@ -817,7 +857,7 @@ static void bind_ctls_for_params(struct state *state)
state->ctl_n_fds = SPA_N_ELEMENTS(state->ctl_sources);
}
if ((err = snd_ctl_poll_descriptors(state->ctl, pfds, state->ctl_n_fds)) < 0) {
if ((err = snd_ctl_poll_descriptors(state->ctl, state->ctl_pfds, state->ctl_n_fds)) < 0) {
spa_log_warn(state->log, "Could not get poll descriptors: %s", snd_strerror(err));
return;
}
@ -827,7 +867,7 @@ static void bind_ctls_for_params(struct state *state)
for (int i = 0; i < state->ctl_n_fds; i++) {
state->ctl_sources[i].func = bind_ctl_event;
state->ctl_sources[i].data = state;
state->ctl_sources[i].fd = pfds[i].fd;
state->ctl_sources[i].fd = state->ctl_pfds[i].fd;
state->ctl_sources[i].mask = SPA_IO_IN;
state->ctl_sources[i].rmask = 0;
spa_loop_add_source(state->main_loop, &state->ctl_sources[i]);

1
spa/plugins/alsa/alsa-pcm.h
View file

@ -259,6 +259,7 @@ struct state {
/* ALSA ctls exposed as params */
unsigned int num_bind_ctls;
struct bound_ctl bound_ctls[16];
struct pollfd ctl_pfds[MAX_POLL];
struct spa_source ctl_sources[MAX_POLL];
int ctl_n_fds;