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authorOswald Buddenhagen <oswald.buddenhagen@gmx.de>2023-05-14 19:03:23 +0200
committerTakashi Iwai <tiwai@suse.de>2023-05-16 11:11:04 +0200
commitbcdbd3b7888e1db89b7b2f7c78237c9ed5c2ebb1 (patch)
tree28e01cac493ddac6d65e345e5bf07dd20219477d /Documentation/sound
parent1298bc978afba0a507cedd0a91e53267ca152804 (diff)
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 'Documentation/sound')
-rw-r--r--Documentation/sound/cards/audigy-mixer.rst2
-rw-r--r--Documentation/sound/cards/sb-live-mixer.rst2
2 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/sound/cards/audigy-mixer.rst b/Documentation/sound/cards/audigy-mixer.rst
index aa176451d5b5..e02dd890d089 100644
--- a/Documentation/sound/cards/audigy-mixer.rst
+++ b/Documentation/sound/cards/audigy-mixer.rst
@@ -227,7 +227,7 @@ PCM stream related controls
name='EMU10K1 PCM Volume',index 0-31
------------------------------------
-Channel volume attenuation in range 0-0xffff. The maximum value (no
+Channel volume attenuation in range 0-0x1fffd. The middle value (no
attenuation) is default. The channel mapping for three values is
as follows:
diff --git a/Documentation/sound/cards/sb-live-mixer.rst b/Documentation/sound/cards/sb-live-mixer.rst
index 819886634400..4dd9bfe01bd8 100644
--- a/Documentation/sound/cards/sb-live-mixer.rst
+++ b/Documentation/sound/cards/sb-live-mixer.rst
@@ -258,7 +258,7 @@ PCM stream related controls
``name='EMU10K1 PCM Volume',index 0-31``
----------------------------------------
-Channel volume attenuation in range 0-0xffff. The maximum value (no
+Channel volume attenuation in range 0-0x1fffd. The middle value (no
attenuation) is default. The channel mapping for three values is
as follows: