ALSA: snd-pcsp: add nopcm mode

Currently, if the high-res timers are unavailable, snd-pcsp does not
initialize. People who choose it over pcspkr, loose their console beeps
in that case and get annoyed.
With this patch, the console beeps remain regardless of the high-res
timers. Additionally, the "nopcm" modparam is added to forcibly
disable the PCM capabilities of the driver.

Signed-off-by: Stas Sergeev <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

Documentation/sound/alsa/ALSA-Configuration.txt

···
 
     Module for internal PC-Speaker.
 
+    nopcm	- Disable PC-Speaker PCM sound. Only beeps remain.
     nforce_wa	- enable NForce chipset workaround. Expect bad sound.
 
     This module supports system beeps, some kind of PCM playback and

sound/drivers/pcsp/pcsp.c

···
 static int index = SNDRV_DEFAULT_IDX1;	/* Index 0-MAX */
 static char *id = SNDRV_DEFAULT_STR1;	/* ID for this card */
 static int enable = SNDRV_DEFAULT_ENABLE1;	/* Enable this card */
+static int nopcm;	/* Disable PCM capability of the driver */
 
 module_param(index, int, 0444);
 MODULE_PARM_DESC(index, "Index value for pcsp soundcard.");
···
 MODULE_PARM_DESC(id, "ID string for pcsp soundcard.");
 module_param(enable, bool, 0444);
 MODULE_PARM_DESC(enable, "Enable PC-Speaker sound.");
+module_param(nopcm, bool, 0444);
+MODULE_PARM_DESC(nopcm, "Disable PC-Speaker PCM sound. Only beeps remain.");
 
 struct snd_pcsp pcsp_chip;
 
···
 	int err;
 	int div, min_div, order;
 
-	hrtimer_get_res(CLOCK_MONOTONIC, &tp);
-	if (tp.tv_sec || tp.tv_nsec > PCSP_MAX_PERIOD_NS) {
-		printk(KERN_ERR "PCSP: Timer resolution is not sufficient "
-		       "(%linS)\n", tp.tv_nsec);
-		printk(KERN_ERR "PCSP: Make sure you have HPET and ACPI "
-		       "enabled.\n");
-		return -EIO;
+	if (!nopcm) {
+		hrtimer_get_res(CLOCK_MONOTONIC, &tp);
+		if (tp.tv_sec || tp.tv_nsec > PCSP_MAX_PERIOD_NS) {
+			printk(KERN_ERR "PCSP: Timer resolution is not sufficient "
+				"(%linS)\n", tp.tv_nsec);
+			printk(KERN_ERR "PCSP: Make sure you have HPET and ACPI "
+				"enabled.\n");
+			printk(KERN_ERR "PCSP: Turned into nopcm mode.\n");
+			nopcm = 1;
+		}
 	}
 
 	if (loops_per_jiffy >= PCSP_MIN_LPJ && tp.tv_nsec <= PCSP_MIN_PERIOD_NS)
···
 		snd_card_free(card);
 		return err;
 	}
-	err = snd_pcsp_new_pcm(&pcsp_chip);
-	if (err < 0) {
-		snd_card_free(card);
-		return err;
+	if (!nopcm) {
+		err = snd_pcsp_new_pcm(&pcsp_chip);
+		if (err < 0) {
+			snd_card_free(card);
+			return err;
+		}
 	}
-	err = snd_pcsp_new_mixer(&pcsp_chip);
+	err = snd_pcsp_new_mixer(&pcsp_chip, nopcm);
 	if (err < 0) {
 		snd_card_free(card);
 		return err;

sound/drivers/pcsp/pcsp.h

···
 extern void pcsp_sync_stop(struct snd_pcsp *chip);
 
 extern int snd_pcsp_new_pcm(struct snd_pcsp *chip);
-extern int snd_pcsp_new_mixer(struct snd_pcsp *chip);
+extern int snd_pcsp_new_mixer(struct snd_pcsp *chip, int nopcm);
 
 #endif

sound/drivers/pcsp/pcsp_mixer.c

···
 	.put =		pcsp_##ctl_type##_put, \
 }
 
-static struct snd_kcontrol_new __devinitdata snd_pcsp_controls[] = {
+static struct snd_kcontrol_new __devinitdata snd_pcsp_controls_pcm[] = {
 	PCSP_MIXER_CONTROL(enable, "Master Playback Switch"),
 	PCSP_MIXER_CONTROL(treble, "BaseFRQ Playback Volume"),
+};
+
+static struct snd_kcontrol_new __devinitdata snd_pcsp_controls_spkr[] = {
 	PCSP_MIXER_CONTROL(pcspkr, "PC Speaker Playback Switch"),
 };
 
-int __devinit snd_pcsp_new_mixer(struct snd_pcsp *chip)
+static int __devinit snd_pcsp_ctls_add(struct snd_pcsp *chip,
+	struct snd_kcontrol_new *ctls, int num)
 {
-	struct snd_card *card = chip->card;
 	int i, err;
-
-	for (i = 0; i < ARRAY_SIZE(snd_pcsp_controls); i++) {
-		err = snd_ctl_add(card,
-				 snd_ctl_new1(snd_pcsp_controls + i,
-					      chip));
+	struct snd_card *card = chip->card;
+	for (i = 0; i < num; i++) {
+		err = snd_ctl_add(card, snd_ctl_new1(ctls + i, chip));
 		if (err < 0)
 			return err;
 	}
+	return 0;
+}
+
+int __devinit snd_pcsp_new_mixer(struct snd_pcsp *chip, int nopcm)
+{
+	int err;
+	struct snd_card *card = chip->card;
+
+	if (!nopcm) {
+		err = snd_pcsp_ctls_add(chip, snd_pcsp_controls_pcm,
+			ARRAY_SIZE(snd_pcsp_controls_pcm));
+		if (err < 0)
+			return err;
+	}
+	err = snd_pcsp_ctls_add(chip, snd_pcsp_controls_spkr,
+		ARRAY_SIZE(snd_pcsp_controls_spkr));
+	if (err < 0)
+		return err;
 
 	strcpy(card->mixername, "PC-Speaker");