ALSA: hda: Fix cached processing coefficient verbs

commit f67be28 upstream.

Intel HD Audio defines Coefficient Index and Processing Coefficient as
separate audio widget controls in the Audio Widget Verb Definitions:
Coefficient Index selects the coefficient slot, while Processing
Coefficient accesses the value at the selected slot.

hda_reg_read_coef() selects the slot with AC_VERB_SET_COEF_INDEX, but
then uses AC_VERB_GET_COEF_INDEX for the value read.  That reads back the
selected index instead of the coefficient value.  hda_reg_write_coef()
has the same issue and builds the value write from AC_VERB_GET_COEF_INDEX
instead of AC_VERB_SET_PROC_COEF.

This only affects the regmap coefficient cache path used by codecs that
set codec->cache_coef.  Direct coefficient helpers already use the normal
SET_COEF_INDEX followed by GET_PROC_COEF or SET_PROC_COEF sequence, which
is likely why this has not been noticed widely.

Use AC_VERB_GET_PROC_COEF for cached coefficient reads and
AC_VERB_SET_PROC_COEF for cached coefficient writes.

Fixes: 40ba66a ("ALSA: hda - Add cache support for COEF read/write")
Cc: stable@vger.kernel.org
Signed-off-by: Xu Rao <raoxu@uniontech.com>
Link: https://patch.msgid.link/DB9023BF2920BA99+20260707132419.1731342-1-raoxu@uniontech.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Xu Rao

sound/hda/core/regmap.c

@@ -214,7 +214,7 @@ static int hda_reg_read_coef(struct hdac_device *codec, unsigned int reg,
 	err = snd_hdac_exec_verb(codec, verb, 0, NULL);
 	if (err < 0)
 		return err;
-	verb = (reg & ~0xfffff) | (AC_VERB_GET_COEF_INDEX << 8);
+	verb = (reg & ~0xfffff) | (AC_VERB_GET_PROC_COEF << 8);
 	return snd_hdac_exec_verb(codec, verb, 0, val);
 }
 
@@ -232,7 +232,7 @@ static int hda_reg_write_coef(struct hdac_device *codec, unsigned int reg,
 	err = snd_hdac_exec_verb(codec, verb, 0, NULL);
 	if (err < 0)
 		return err;
-	verb = (reg & ~0xfffff) | (AC_VERB_GET_COEF_INDEX << 8) |
+	verb = (reg & ~0xfffff) | (AC_VERB_SET_PROC_COEF << 8) |
 		(val & 0xffff);
 	return snd_hdac_exec_verb(codec, verb, 0, NULL);
 }