ALSA: timer: add config item to export PCM timer disabling for expert

PCM timer is not always used. For embedded device, we need an interface
to disable it when it is not needed, to shrink the kernel size and
memory footprint, here add CONFIG_SND_PCM_TIMER for it.

When both CONFIG_SND_PCM_TIMER and CONFIG_SND_TIMER is unselected,
about 25KB saving bonus we can get.

Please be noted that when disabled, those stubs who using pcm timer
(e.g. dmix, dsnoop & co) may work incorrectlly.

Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

4 files changed, 32 insertions, 22 deletions

diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index 6c96fee..e3e9491 100644
--- a/sound/core/Kconfig
+++ b/sound/core/Kconfig
@@ -4,7 +4,7 @@ config SND_TIMER
 
 config SND_PCM
 	tristate
-	select SND_TIMER
+	select SND_TIMER if SND_PCM_TIMER
 
 config SND_PCM_ELD
 	bool
@@ -93,6 +93,17 @@ config SND_PCM_OSS_PLUGINS
           support conversion of channels, formats and rates. It will
           behave like most of new OSS/Free drivers in 2.4/2.6 kernels.
 
+config SND_PCM_TIMER
+	bool "PCM timer interface" if EXPERT
+	default y
+	help
+	  If you disable this option, pcm timer will be inavailable, so
+	  those stubs used pcm timer (e.g. dmix, dsnoop & co) may work
+	  incorrectlly.
+
+	  For some embedded device, we may disable it to reduce memory
+	  footprint, about 20KB on x86_64 platform.
+
 config SND_SEQUENCER_OSS
 	bool "OSS Sequencer API"
 	depends on SND_SEQUENCER
diff --git a/sound/core/Makefile b/sound/core/Makefile
index 3354f91..48ab4b8 100644
--- a/sound/core/Makefile
+++ b/sound/core/Makefile
@@ -13,8 +13,9 @@ snd-$(CONFIG_SND_OSSEMUL) += sound_oss.o
 snd-$(CONFIG_SND_VMASTER) += vmaster.o
 snd-$(CONFIG_SND_JACK)	  += ctljack.o jack.o
 
-snd-pcm-y := pcm.o pcm_native.o pcm_lib.o pcm_timer.o pcm_misc.o \
+snd-pcm-y := pcm.o pcm_native.o pcm_lib.o pcm_misc.o \
 		pcm_memory.o memalloc.o
+snd-pcm-$(CONFIG_SND_PCM_TIMER) += pcm_timer.o
 snd-pcm-$(CONFIG_SND_DMA_SGBUF) += sgbuf.o
 snd-pcm-$(CONFIG_SND_PCM_ELD) += pcm_drm_eld.o
 snd-pcm-$(CONFIG_SND_PCM_IEC958) += pcm_iec958.o
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 7d45645..6dc4277 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1883,8 +1883,10 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
 	    snd_pcm_update_hw_ptr0(substream, 1) < 0)
 		goto _end;
 
+#ifdef CONFIG_SND_PCM_TIMER
 	if (substream->timer_running)
 		snd_timer_interrupt(substream->timer, 1);
+#endif
  _end:
 	snd_pcm_stream_unlock_irqrestore(substream, flags);
 	if (runtime->transfer_ack_end)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 13988701..a8b27cd 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -486,6 +486,16 @@ static void snd_pcm_set_state(struct snd_pcm_substream *substream, int state)
 	snd_pcm_stream_unlock_irq(substream);
 }
 
+static inline void snd_pcm_timer_notify(struct snd_pcm_substream *substream,
+					int event)
+{
+#ifdef CONFIG_SND_PCM_TIMER
+	if (substream->timer)
+		snd_timer_notify(substream->timer, event,
+					&substream->runtime->trigger_tstamp);
+#endif
+}
+
 static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
 			     struct snd_pcm_hw_params *params)
 {
@@ -1043,9 +1053,7 @@ static void snd_pcm_post_start(struct snd_pcm_substream *substream, int state)
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
 	    runtime->silence_size > 0)
 		snd_pcm_playback_silence(substream, ULONG_MAX);
-	if (substream->timer)
-		snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSTART,
-				 &runtime->trigger_tstamp);
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSTART);
 }
 
 static struct action_ops snd_pcm_action_start = {
@@ -1093,9 +1101,7 @@ static void snd_pcm_post_stop(struct snd_pcm_substream *substream, int state)
 	if (runtime->status->state != state) {
 		snd_pcm_trigger_tstamp(substream);
 		runtime->status->state = state;
-		if (substream->timer)
-			snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSTOP,
-					 &runtime->trigger_tstamp);
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSTOP);
 	}
 	wake_up(&runtime->sleep);
 	wake_up(&runtime->tsleep);
@@ -1209,18 +1215,12 @@ static void snd_pcm_post_pause(struct snd_pcm_substream *substream, int push)
 	snd_pcm_trigger_tstamp(substream);
 	if (push) {
 		runtime->status->state = SNDRV_PCM_STATE_PAUSED;
-		if (substream->timer)
-			snd_timer_notify(substream->timer,
-					 SNDRV_TIMER_EVENT_MPAUSE,
-					 &runtime->trigger_tstamp);
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MPAUSE);
 		wake_up(&runtime->sleep);
 		wake_up(&runtime->tsleep);
 	} else {
 		runtime->status->state = SNDRV_PCM_STATE_RUNNING;
-		if (substream->timer)
-			snd_timer_notify(substream->timer,
-					 SNDRV_TIMER_EVENT_MCONTINUE,
-					 &runtime->trigger_tstamp);
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MCONTINUE);
 	}
 }
 
@@ -1268,9 +1268,7 @@ static void snd_pcm_post_suspend(struct snd_pcm_substream *substream, int state)
 	snd_pcm_trigger_tstamp(substream);
 	runtime->status->suspended_state = runtime->status->state;
 	runtime->status->state = SNDRV_PCM_STATE_SUSPENDED;
-	if (substream->timer)
-		snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSUSPEND,
-				 &runtime->trigger_tstamp);
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSUSPEND);
 	wake_up(&runtime->sleep);
 	wake_up(&runtime->tsleep);
 }
@@ -1374,9 +1372,7 @@ static void snd_pcm_post_resume(struct snd_pcm_substream *substream, int state)
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	snd_pcm_trigger_tstamp(substream);
 	runtime->status->state = runtime->status->suspended_state;
-	if (substream->timer)
-		snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MRESUME,
-				 &runtime->trigger_tstamp);
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MRESUME);
 }
 
 static struct action_ops snd_pcm_action_resume = {