ALSA: emu10k1: don't restrict capture channel count to powers of two

The hardware can deal with primes up to 7 and power-of-two multiples
thereof; the limitation is reflected by the possible buffer sizes.

Note that setting the voice mask will not allow more than 16 channels
even on Sound Blaster Audigy anymore, as 32 seems a bit excessive (the
code overall appears to think so, just not in this case).

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230523200709.236059-4-oswald.buddenhagen@gmx.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 19 insertions, 8 deletions

diff --git a/sound/pci/emu10k1/emupcm.c b/sound/pci/emu10k1/emupcm.c
index 8279d8a4f589..4216df399305 100644
--- a/sound/pci/emu10k1/emupcm.c
+++ b/sound/pci/emu10k1/emupcm.c
@@ -122,6 +122,17 @@ static int snd_emu10k1_pcm_channel_alloc(struct snd_emu10k1_pcm *epcm,
 	return 0;
 }
 
+// Primes 2-7 and 2^n multiples thereof, up to 16.
+static const unsigned int efx_capture_channels[] = {
+	1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16
+};
+
+static const struct snd_pcm_hw_constraint_list hw_constraints_efx_capture_channels = {
+	.count = ARRAY_SIZE(efx_capture_channels),
+	.list = efx_capture_channels,
+	.mask = 0
+};
+
 static const unsigned int capture_buffer_sizes[31] = {
 	384,	448,	512,	640,
 	384*2,	448*2,	512*2,	640*2,
@@ -1281,7 +1292,7 @@ static int snd_emu10k1_capture_efx_open(struct snd_pcm_substream *substream)
 	struct snd_emu10k1_pcm *epcm;
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	int nefx = emu->audigy ? 64 : 32;
-	int idx;
+	int idx, err;
 
 	epcm = kzalloc(sizeof(*epcm), GFP_KERNEL);
 	if (epcm == NULL)
@@ -1367,6 +1378,12 @@ static int snd_emu10k1_capture_efx_open(struct snd_pcm_substream *substream)
 	epcm->capture_cr_val = emu->efx_voices_mask[0];
 	epcm->capture_cr_val2 = emu->efx_voices_mask[1];
 	spin_unlock_irq(&emu->reg_lock);
+	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
+					 &hw_constraints_efx_capture_channels);
+	if (err < 0) {
+		kfree(epcm);
+		return err;
+	}
 	snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
 				   &hw_constraints_capture_buffer_sizes);
 	emu->capture_efx_interrupt = snd_emu10k1_pcm_efx_interrupt;
@@ -1531,7 +1548,6 @@ static int snd_emu10k1_pcm_efx_voices_mask_put(struct snd_kcontrol *kcontrol, st
 	struct snd_emu10k1 *emu = snd_kcontrol_chip(kcontrol);
 	unsigned int nval[2], bits;
 	int nefx = emu->audigy ? 64 : 32;
-	int nefxb = emu->audigy ? 7 : 6;
 	int change, idx;
 	
 	nval[0] = nval[1] = 0;
@@ -1541,12 +1557,7 @@ static int snd_emu10k1_pcm_efx_voices_mask_put(struct snd_kcontrol *kcontrol, st
 			bits++;
 		}
 
-	// Check that the number of requested channels is a power of two
-	// not bigger than the number of available channels.
-	for (idx = 0; idx < nefxb; idx++)
-		if (1 << idx == bits)
-			break;
-	if (idx >= nefxb)
+	if (bits == 9 || bits == 11 || bits == 13 || bits == 15 || bits > 16)
 		return -EINVAL;
 
 	spin_lock_irq(&emu->reg_lock);