ALSA: via82xx: allow to disable the SRC

Add the PCM rule to allow disabling the PCM playback SRC.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/via82xx.c

@@ -1175,6 +1175,7 @@ static int snd_via82xx_pcm_open(struct via82xx *chip, struct viadev *viadev,
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	int err;
 	struct via_rate_lock *ratep;
+	bool use_src = false;
 
 	runtime->hw = snd_via82xx_hw;
 	
@@ -1196,6 +1197,7 @@ static int snd_via82xx_pcm_open(struct via82xx *chip, struct viadev *viadev,
 				     SNDRV_PCM_RATE_8000_48000);
 		runtime->hw.rate_min = 8000;
 		runtime->hw.rate_max = 48000;
+		use_src = true;
 	} else if (! ratep->rate) {
 		int idx = viadev->direction ? AC97_RATES_ADC : AC97_RATES_FRONT_DAC;
 		runtime->hw.rates = chip->ac97->rates[idx];
@@ -1212,6 +1214,12 @@ static int snd_via82xx_pcm_open(struct via82xx *chip, struct viadev *viadev,
 	if ((err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS)) < 0)
 		return err;
 
+	if (use_src) {
+		err = snd_pcm_hw_rule_noresample(runtime, 48000);
+		if (err < 0)
+			return err;
+	}
+
 	runtime->private_data = viadev;
 	viadev->substream = substream;