Revert "ALSA: emu10k1 - delay the PCM interrupts (add pcm_irq_delay parameter)"

This workaround fails to address the underlying problem, which is
actually wholly self-made. Subsequent patches will fix it.

This reverts commit 56385a12.
Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230517174256.3657060-2-oswald.buddenhagen@gmx.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/emu10k1.h

@@ -1670,7 +1670,6 @@ struct snd_emu10k1 {
 	unsigned int address_mode;		/* address mode */
 	unsigned long dma_mask;			/* PCI DMA mask */
 	bool iommu_workaround;			/* IOMMU workaround needed */
-	unsigned int delay_pcm_irq;		/* in samples */
 	int max_cache_pages;			/* max memory size / PAGE_SIZE */
 	struct snd_dma_buffer silent_page;	/* silent page */
 	struct snd_dma_buffer ptb_pages;	/* page table pages */

sound/core/pcm_native.c

@@ -1605,10 +1605,6 @@ static int snd_pcm_do_pause(struct snd_pcm_substream *substream,
 {
 	if (substream->runtime->trigger_master != substream)
 		return 0;
-	/* some drivers might use hw_ptr to recover from the pause -
-	   update the hw_ptr now */
-	if (pause_pushed(state))
-		snd_pcm_update_hw_ptr(substream);
 	/* The jiffies check in snd_pcm_update_hw_ptr*() is done by
 	 * a delta between the current jiffies, this gives a large enough
 	 * delta, effectively to skip the check once.

sound/pci/emu10k1/emu10k1.c

@@ -34,7 +34,6 @@ static int max_synth_voices[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 64};
 static int max_buffer_size[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 128};
 static bool enable_ir[SNDRV_CARDS];
 static uint subsystem[SNDRV_CARDS]; /* Force card subsystem model */
-static uint delay_pcm_irq[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
 
 module_param_array(index, int, NULL, 0444);
 MODULE_PARM_DESC(index, "Index value for the EMU10K1 soundcard.");
@@ -56,8 +55,6 @@ module_param_array(enable_ir, bool, NULL, 0444);
 MODULE_PARM_DESC(enable_ir, "Enable IR.");
 module_param_array(subsystem, uint, NULL, 0444);
 MODULE_PARM_DESC(subsystem, "Force card subsystem model.");
-module_param_array(delay_pcm_irq, uint, NULL, 0444);
-MODULE_PARM_DESC(delay_pcm_irq, "Delay PCM interrupt by specified number of samples (default 0).");
 /*
  * Class 0401: 1102:0008 (rev 00) Subsystem: 1102:1001 -> Audigy2 Value  Model:SB0400
  */
@@ -103,7 +100,6 @@ static int snd_card_emu10k1_probe(struct pci_dev *pci,
 				 enable_ir[dev], subsystem[dev]);
 	if (err < 0)
 		return err;
-	emu->delay_pcm_irq = delay_pcm_irq[dev] & 0x1f;
 	err = snd_emu10k1_pcm(emu, 0);
 	if (err < 0)
 		return err;

sound/pci/emu10k1/emupcm.c

@@ -290,7 +290,7 @@ static void snd_emu10k1_pcm_init_voice(struct snd_emu10k1 *emu,
 		evoice->epcm->ccca_start_addr = start_addr + ccis;
 		if (extra) {
 			start_addr += ccis;
-			end_addr += ccis + emu->delay_pcm_irq;
+			end_addr += ccis;
 		}
 	}
 	if (stereo && !extra) {
@@ -315,9 +315,7 @@ static void snd_emu10k1_pcm_init_voice(struct snd_emu10k1 *emu,
 	snd_emu10k1_ptr_write(emu, PTRX, voice, (send_amount[0] << 8) | send_amount[1]);
 	// Stereo slaves don't need to have the addresses set, but it doesn't hurt
 	snd_emu10k1_ptr_write(emu, DSL, voice, end_addr | (send_amount[3] << 24));
-	snd_emu10k1_ptr_write(emu, PSST, voice,
-			(start_addr + (extra ? emu->delay_pcm_irq : 0)) |
-			(send_amount[2] << 24));
+	snd_emu10k1_ptr_write(emu, PSST, voice, start_addr | (send_amount[2] << 24));
 	if (emu->card_capabilities->emu_model)
 		pitch_target = PITCH_48000; /* Disable interpolators on emu1010 card */
 	else 
@@ -647,23 +645,6 @@ static void snd_emu10k1_playback_set_stopped(struct snd_emu10k1 *emu,
 	epcm->running = 0;
 }
 
-static inline void snd_emu10k1_playback_mangle_extra(struct snd_emu10k1 *emu,
-		struct snd_emu10k1_pcm *epcm,
-		struct snd_pcm_substream *substream,
-		struct snd_pcm_runtime *runtime)
-{
-	unsigned int ptr, period_pos;
-
-	/* try to sychronize the current position for the interrupt
-	   source voice */
-	period_pos = runtime->status->hw_ptr - runtime->hw_ptr_interrupt;
-	period_pos %= runtime->period_size;
-	ptr = snd_emu10k1_ptr_read(emu, CCCA, epcm->extra->number);
-	ptr &= ~0x00ffffff;
-	ptr |= epcm->ccca_start_addr + period_pos;
-	snd_emu10k1_ptr_write(emu, CCCA, epcm->extra->number, ptr);
-}
-
 static int snd_emu10k1_playback_trigger(struct snd_pcm_substream *substream,
 				        int cmd)
 {
@@ -686,8 +667,6 @@ static int snd_emu10k1_playback_trigger(struct snd_pcm_substream *substream,
 		fallthrough;
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 	case SNDRV_PCM_TRIGGER_RESUME:
-		if (cmd == SNDRV_PCM_TRIGGER_PAUSE_RELEASE)
-			snd_emu10k1_playback_mangle_extra(emu, epcm, substream, runtime);
 		mix = &emu->pcm_mixer[substream->number];
 		snd_emu10k1_playback_unmute_voice(emu, epcm->voices[0], true, mix);
 		snd_emu10k1_playback_unmute_voice(emu, epcm->voices[1], false, mix);

sound/pci/emu10k1/memory.c

@@ -315,10 +315,8 @@ snd_emu10k1_alloc_pages(struct snd_emu10k1 *emu, struct snd_pcm_substream *subst
 	if (snd_BUG_ON(!hdr))
 		return NULL;
 
-	idx = runtime->period_size >= runtime->buffer_size ?
-					(emu->delay_pcm_irq * 2) : 0;
 	mutex_lock(&hdr->block_mutex);
-	blk = search_empty(emu, runtime->dma_bytes + idx);
+	blk = search_empty(emu, runtime->dma_bytes);
 	if (blk == NULL) {
 		mutex_unlock(&hdr->block_mutex);
 		return NULL;