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authorOswald Buddenhagen <oswald.buddenhagen@gmx.de>2023-05-16 11:36:11 +0200
committerTakashi Iwai <tiwai@suse.de>2023-05-17 17:04:35 +0200
commit77e067d0fa0511daec7e4c72ec3f830e5faaee9e (patch)
tree1911452e67ec3b0aaf8d06b008f4ba09b74d4872 /include/sound/emu10k1.h
parent35a60d1edff4dec9a31862a3515676cd0fafe4e4 (diff)
ALSA: emu10k1: skip needless setting of some voice registers
Many registers are meaningless for stereo slaves and the extra voices. This patch cleans up these unnecessary register writes. snd_emu10k1_playback_{trigger,stop}_voice() is not called for stereo slaves any more. snd_emu10k1_playback_prepare_voice() is renamed to snd_emu10k1_playback_unmute_voice(), as this better reflects its remaining function. It's not called for the extra voices any more. Accordingly, snd_emu10k1_playback_mute_voice() is factored out from snd_emu10k1_playback_stop_voice(), and is called selectively as well. This doesn't add conditionals which would avoid initializing sub-registers, as that wouldn't pull its weight. Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de> Link: https://lore.kernel.org/r/20230516093612.3536451-6-oswald.buddenhagen@gmx.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include/sound/emu10k1.h')
-rw-r--r--include/sound/emu10k1.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/sound/emu10k1.h b/include/sound/emu10k1.h
index a5e935e16651..5c1e5b123362 100644
--- a/include/sound/emu10k1.h
+++ b/include/sound/emu10k1.h
@@ -404,6 +404,14 @@ SUB_REG(HCFG, LOCKTANKCACHE, 0x00000004) /* 1 = Cancel bustmaster accesses to ta
// distortion), the modulation engine sets the target registers, towards
// which the current registers "swerve" gradually.
+// For the odd channel in a stereo pair, these registers are meaningless:
+// CPF_STEREO, CPF_CURRENTPITCH, PTRX_PITCHTARGET, CCR_CACHEINVALIDSIZE,
+// PSST_LOOPSTARTADDR, DSL_LOOPENDADDR, CCCA_CURRADDR
+// The somewhat non-obviously still meaningful ones are:
+// CPF_STOP, CPF_FRACADDRESS, CCR_READADDRESS (!),
+// CCCA_INTERPROM, CCCA_8BITSELECT (!)
+// (The envelope engine is ignored here, as stereo matters only for verbatim playback.)
+
#define CPF 0x00 /* Current pitch and fraction register */
SUB_REG(CPF, CURRENTPITCH, 0xffff0000) /* Current pitch (linear, 0x4000 == unity pitch shift) */
#define CPF_STEREO_MASK 0x00008000 /* 1 = Even channel interleave, odd channel locked */