alsa: optimistically try resuming from suspend

Apparently snd_pcm_hw_params_can_resume() can return false even though my hardware does in fact support resuming. So stop carrying that value in the canResume flag and just try to resume when we're in the suspended state; falling back to snd_pcm_prepare only if resuming fails. libao does something similar on resume, too. While we're at it, use the E() macro which will enable us to have better error reporting. [mk: remove the E() macro stuff]

alsa: optimistically try resuming from suspend
7bd98c08 · Eric Wong · Max Kellermann · da1e8584 · 7bd98c08
Commit 7bd98c08 authored Sep 08, 2008 by Eric Wong Committed by Max Kellermann Sep 08, 2008
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audioOutput_alsa.c src/audioOutputs/audioOutput_alsa.c +4 -6

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--- a/src/audioOutputs/audioOutput_alsa.c
+++ b/src/audioOutputs/audioOutput_alsa.c
@@ -47,7 +47,6 @@ typedef struct _AlsaData {
 	int sampleSize;
 	int useMmap;
 	int canPause;
-	int canResume;
 } AlsaData;
 static AlsaData *newAlsaData(void)
@@ -262,7 +261,6 @@ configure_hw:
 		goto error;
 	ad->canPause = snd_pcm_hw_params_can_pause(hwparams);
-	ad->canResume = snd_pcm_hw_params_can_resume(hwparams);
 	/* configure SW params */
 	snd_pcm_sw_params_alloca(&swparams);
@@ -334,10 +332,10 @@ static int alsa_errorRecovery(AlsaData * ad, int err)
 		err = snd_pcm_pause(ad->pcmHandle, /* disable */ 0);
 		break;
 	case SND_PCM_STATE_SUSPENDED:
-		err = ad->canResume ?
+		err = snd_pcm_resume(ad->pcmHandle);
-		    snd_pcm_resume(ad->pcmHandle) :
+		if (err == -EAGAIN)
-		    snd_pcm_prepare(ad->pcmHandle);
+			return 0;
-		break;
+		/* fall-through to snd_pcm_prepare: */
 	case SND_PCM_STATE_SETUP:
 	case SND_PCM_STATE_XRUN:
 		err = snd_pcm_prepare(ad->pcmHandle);