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| author | Oswald Buddenhagen <oswald.buddenhagen@gmx.de> | 2023-05-14 20:03:23 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2023-05-16 12:11:04 +0300 |
| commit | bcdbd3b7888e1db89b7b2f7c78237c9ed5c2ebb1 (patch) | |
| tree | 28e01cac493ddac6d65e345e5bf07dd20219477d /sound/pci/emu10k1/emupcm.c | |
| parent | 1298bc978afba0a507cedd0a91e53267ca152804 (diff) | |
| download | linux-bcdbd3b7888e1db89b7b2f7c78237c9ed5c2ebb1.tar.xz | |
ALSA: emu10k1: enable bit-exact playback, part 2: voice attenuation
The voice volume is a raw fractional multiplier that can't actually
represent 1.0. To still enable real pass-through, we now set the volume
to 0.5 (which results in no loss of precision, as the FX bus provides
fractional values) and scale up the samples in DSP code.
To maintain backwards compatibility with existing configuration files,
we rescale the values in the mixer controls. The range is extended
upwards from 0xffff to 0x1fffd, which actually introduces the
possibility of specifying an amplification.
There is still a minor incompatibility with user space, namely if
someone loaded custom DSP code. They'll just get half the volume, so
this doesn't seem like a big deal.
Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230514170323.3408834-8-oswald.buddenhagen@gmx.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/pci/emu10k1/emupcm.c')
| -rw-r--r-- | sound/pci/emu10k1/emupcm.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sound/pci/emu10k1/emupcm.c b/sound/pci/emu10k1/emupcm.c index 5ed404e8ed39..6e6d3103ed90 100644 --- a/sound/pci/emu10k1/emupcm.c +++ b/sound/pci/emu10k1/emupcm.c @@ -1049,7 +1049,7 @@ static int snd_emu10k1_efx_playback_open(struct snd_pcm_substream *substream) mix->send_routing[0][0] = i; memset(&mix->send_volume, 0, sizeof(mix->send_volume)); mix->send_volume[0][0] = 255; - mix->attn[0] = 0xffff; + mix->attn[0] = 0x8000; mix->epcm = epcm; snd_emu10k1_pcm_efx_mixer_notify(emu, i, 1); } @@ -1098,7 +1098,7 @@ static int snd_emu10k1_playback_open(struct snd_pcm_substream *substream) memset(&mix->send_volume, 0, sizeof(mix->send_volume)); mix->send_volume[0][0] = mix->send_volume[0][1] = mix->send_volume[1][0] = mix->send_volume[2][1] = 255; - mix->attn[0] = mix->attn[1] = mix->attn[2] = 0xffff; + mix->attn[0] = mix->attn[1] = mix->attn[2] = 0x8000; mix->epcm = epcm; snd_emu10k1_pcm_mixer_notify(emu, substream->number, 1); return 0; |