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ErosQ (both): avoid clipping due to DC offset bandaid

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Set the maximum volume on both hosted and native ports
to -2 dB.

Verified behavior here on native and by borkitall on irc
for hosted.

Change-Id: I3aebc2bb4b9294a4137a33694c83139c0d76099a
This commit is contained in:
Dana Conrad 2021-09-03 21:56:28 -05:00
parent 3e52c7c734
commit 17263a813b
2 changed files with 16 additions and 3 deletions
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10
firmware/export/eros_qn_codec.h
View file

@ -23,10 +23,16 @@
#ifndef _EROS_QN_CODEC_H #ifndef _EROS_QN_CODEC_H
#define _EROS_QN_CODEC_H #define _EROS_QN_CODEC_H
/*
* Note: Maximum volume is set one step below unity in order to
* avoid overflowing pcm samples due to our DC Offset.
*
* The DAC's output is hot enough this should not be an issue.
*/
#define PCM5102A_VOLUME_MIN -740 #define PCM5102A_VOLUME_MIN -740
#define PCM5102A_VOLUME_MAX 0 #define PCM5102A_VOLUME_MAX -20
/* a small DC offset appears to prevent play/pause clicking */ /* a small DC offset prevents play/pause clicking due to the DAC auto-muting */
#define PCM_DC_OFFSET_VALUE -1 #define PCM_DC_OFFSET_VALUE -1
AUDIOHW_SETTING(VOLUME, "dB", 0, 2, PCM5102A_VOLUME_MIN/10, PCM5102A_VOLUME_MAX/10, 0) AUDIOHW_SETTING(VOLUME, "dB", 0, 2, PCM5102A_VOLUME_MIN/10, PCM5102A_VOLUME_MAX/10, 0)

9
firmware/export/erosqlinux_codec.h
View file

@ -3,9 +3,16 @@
#define AUDIOHW_CAPS (LINEOUT_CAP) #define AUDIOHW_CAPS (LINEOUT_CAP)
/* a small DC offset prevents play/pause clicking due to the DAC auto-muting */
#define PCM_DC_OFFSET_VALUE -1 #define PCM_DC_OFFSET_VALUE -1
AUDIOHW_SETTING(VOLUME, "dB", 0, 2, -74, 0, -40) /*
* Note: Maximum volume is set one step below unity in order to
* avoid overflowing pcm samples due to our DC Offset.
*
* The DAC's output is hot enough this should not be an issue.
*/
AUDIOHW_SETTING(VOLUME, "dB", 0, 2, -74, -2, -40)
//#define AUDIOHW_NEEDS_INITIAL_UNMUTE //#define AUDIOHW_NEEDS_INITIAL_UNMUTE