Revert "ALSA: emu10k1: fix synthesizer sample playback position and caching"

As already anticipated in the original commit, playback was broken for
very short samples. I just didn't expect it to be an actual problem,
because we're talking about less than 1.5 milliseconds here. But clearly
such wavetable samples do actually exist.

The problem was that for such short samples we'd set the current
position beyond the end of the loop, so we'd run off the end of the
sample and play garbage.
This is a bigger (more audible) problem than the original one, which was
that we'd start playback with garbage (whatever was still in the cache),
which would be mostly masked by the note's attack phase.

So revert to the old behavior for now. We'll subsequently fix it
properly with a bigger patch series.
Note that this isn't a full revert - the dead code is not re-introduced,
because that would be silly.

Fixes: df335e9 ("ALSA: emu10k1: fix synthesizer sample playback position and caching")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218625
Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Message-ID: <20240401145805.528794-1-oswald.buddenhagen@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Author: ossilator

sound/pci/emu10k1/emu10k1_callback.c

@@ -255,7 +255,7 @@ lookup_voices(struct snd_emux *emu, struct snd_emu10k1 *hw,
 		/* check if sample is finished playing (non-looping only) */
 		if (bp != best + V_OFF && bp != best + V_FREE &&
 		    (vp->reg.sample_mode & SNDRV_SFNT_SAMPLE_SINGLESHOT)) {
-			val = snd_emu10k1_ptr_read(hw, CCCA_CURRADDR, vp->ch) - 64;
+			val = snd_emu10k1_ptr_read(hw, CCCA_CURRADDR, vp->ch);
 			if (val >= vp->reg.loopstart)
 				bp = best + V_OFF;
 		}
@@ -362,7 +362,7 @@ start_voice(struct snd_emux_voice *vp)
 
 	map = (hw->silent_page.addr << hw->address_mode) | (hw->address_mode ? MAP_PTI_MASK1 : MAP_PTI_MASK0);
 
-	addr = vp->reg.start + 64;
+	addr = vp->reg.start;
 	temp = vp->reg.parm.filterQ;
 	ccca = (temp << 28) | addr;
 	if (vp->apitch < 0xe400)
@@ -430,9 +430,6 @@ start_voice(struct snd_emux_voice *vp)
 		/* Q & current address (Q 4bit value, MSB) */
 		CCCA, ccca,
 
-		/* cache */
-		CCR, REG_VAL_PUT(CCR_CACHEINVALIDSIZE, 64),
-
 		/* reset volume */
 		VTFT, vtarget | vp->ftarget,
 		CVCF, vtarget | CVCF_CURRENTFILTER_MASK,