[PATCH] ALSA: scarlett2: Fix Scarlett 4th Gen input gain range again

[PATCH] ALSA: scarlett2: Fix Scarlett 4th Gen input gain range again

[Geoffrey D. Bennett]

The 4th Gen input preamp gain range is 0dB to +69dB, although the
control values range from 0 to 70. Replace SCARLETT2_MAX_GAIN with
SCARLETT2_MAX_GAIN_VALUE and SCARLETT2_MAX_GAIN_DB, and update the TLV
again.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Fixes: a45cf0a08347 ("ALSA: scarlett2: Fix Scarlett 4th Gen input gain range")
---
 sound/usb/mixer_scarlett2.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
index ffb8bcebf9ad..bd114be537d7 100644
--- a/sound/usb/mixer_scarlett2.c
+++ b/sound/usb/mixer_scarlett2.c
@@ -174,8 +174,11 @@
 /* some gui mixers can't handle negative ctl values */
 #define SCARLETT2_VOLUME_BIAS 127
 
-/* maximum preamp input gain */
-#define SCARLETT2_MAX_GAIN 70
+/* maximum preamp input gain and value
+ * values are from 0 to 70, preamp gain is from 0 to 69 dB
+ */
+#define SCARLETT2_MAX_GAIN_VALUE 70
+#define SCARLETT2_MAX_GAIN_DB 69
 
 /* mixer range from -80dB to +6dB in 0.5dB steps */
 #define SCARLETT2_MIXER_MIN_DB -80
@@ -3466,7 +3469,7 @@ static int scarlett2_input_gain_ctl_info(struct snd_kcontrol *kctl,
 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 	uinfo->count = elem->channels;
 	uinfo->value.integer.min = 0;
-	uinfo->value.integer.max = SCARLETT2_MAX_GAIN;
+	uinfo->value.integer.max = SCARLETT2_MAX_GAIN_VALUE;
 	uinfo->value.integer.step = 1;
 
 unlock:
@@ -3543,7 +3546,7 @@ static int scarlett2_input_gain_ctl_put(struct snd_kcontrol *kctl,
 }
 
 static const DECLARE_TLV_DB_MINMAX(
-	db_scale_scarlett2_gain, 0, SCARLETT2_MAX_GAIN * 100
+	db_scale_scarlett2_gain, 0, SCARLETT2_MAX_GAIN_DB * 100
 );
 
 static const struct snd_kcontrol_new scarlett2_input_gain_ctl = {
-- 
2.43.0

Re: [PATCH] ALSA: scarlett2: Fix Scarlett 4th Gen input gain range again

[Takashi Iwai]

On Mon, 11 Mar 2024 10:26:08 +0100,
Geoffrey D. Bennett wrote:
> 
> The 4th Gen input preamp gain range is 0dB to +69dB, although the
> control values range from 0 to 70. Replace SCARLETT2_MAX_GAIN with
> SCARLETT2_MAX_GAIN_VALUE and SCARLETT2_MAX_GAIN_DB, and update the TLV
> again.
> 
> Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
> Fixes: a45cf0a08347 ("ALSA: scarlett2: Fix Scarlett 4th Gen input gain range")

Thanks, applied now.


Takashi