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erosq: Switch to 32-bit PCM output, and do volume scaling in driver 

Should improve audio output quality, especially at lower volumes.

Change-Id: I31c38f05fe4b554b092511f0fe7aaad9f346f6c5
This commit is contained in:
Solomon Peachy 2021-04-08 23:58:49 -04:00
parent e86d90905b
commit 1e2a9a651c
4 changed files with 14 additions and 12 deletions
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19
firmware/drivers/audio/erosqlinux_codec.c
View File

@ -169,6 +169,10 @@ void audiohw_set_frequency(int fsel)
(void)fsel;
}
/* min/max for pcm volume */
const int min_pcm = -430;
const int max_pcm = 0;
void audiohw_set_volume(int vol_l, int vol_r)
{
logf("hw vol %d %d", vol_l, vol_r);
@ -179,7 +183,7 @@ void audiohw_set_volume(int vol_l, int vol_r)
vol_r_hw = vol_r;
if (lineout_inserted()) {
/* On the EROS Q/K hardware, line out is _very_ hot
/* On the EROS Q/K hardware, full scale line out is _very_ hot
at ~5.8Vpp. As the hardware provides no way to reduce
output gain, we have to back off on the PCM signal
to avoid blowing out the signal.
@ -190,10 +194,9 @@ void audiohw_set_volume(int vol_l, int vol_r)
r = vol_r_hw;
}
/* SW volume for <= 1.0 gain, HW at unity, < -740 == MUTE */
int sw_volume_l = l <= -740 ? PCM_MUTE_LEVEL : MIN(l, 0);
int sw_volume_r = r <= -740 ? PCM_MUTE_LEVEL : MIN(r, 0);
pcm_set_master_volume(sw_volume_l, sw_volume_r);
int sw_volume_l = l <= min_pcm ? min_pcm : MIN(l, max_pcm);
int sw_volume_r = r <= min_pcm ? min_pcm : MIN(r, max_pcm);
pcm_set_mixer_volume(sw_volume_l / 10, sw_volume_r / 10);
}
void audiohw_set_lineout_volume(int vol_l, int vol_r)
@ -212,7 +215,7 @@ void audiohw_set_lineout_volume(int vol_l, int vol_r)
r = vol_r_hw;
}
int sw_volume_l = l <= -740 ? PCM_MUTE_LEVEL : MIN(l, 0);
int sw_volume_r = r <= -740 ? PCM_MUTE_LEVEL : MIN(r, 0);
pcm_set_master_volume(sw_volume_l, sw_volume_r);
int sw_volume_l = l <= min_pcm ? min_pcm : MIN(l, max_pcm);
int sw_volume_r = r <= min_pcm ? min_pcm : MIN(r, max_pcm);
pcm_set_mixer_volume(sw_volume_l / 10, sw_volume_r / 10);
}

3
firmware/export/config/aigoerosq.h
View File

@ -36,8 +36,7 @@
/* Audio codec */
#define HAVE_EROSQ_LINUX_CODEC
/* Rockbox has to handle the volume level */
#define HAVE_SW_VOLUME_CONTROL
#define HAVE_ALSA_32BIT
/* We don't have hardware controls */
#define HAVE_SW_TONE_CONTROLS

2
firmware/export/erosqlinux_codec.h
View File

@ -3,7 +3,7 @@
#define AUDIOHW_CAPS (LINEOUT_CAP)
AUDIOHW_SETTING(VOLUME, "dB", 0, 1, -74, 6, -25)
AUDIOHW_SETTING(VOLUME, "dB", 0, 1, -43, 0, -20)
//#define AUDIOHW_NEEDS_INITIAL_UNMUTE

2
firmware/target/hosted/pcm-alsa.c
View File

@ -277,7 +277,7 @@ static int dig_vol_mult_r = 2 << 16; /* multiplicative factor to apply to each s
void pcm_set_mixer_volume(int vol_db_l, int vol_db_r)
{
if(vol_db_l > 0 || vol_db_r > 0 || vol_db_l < -43 || vol_db_r < -43)
panicf("invalid pcm alsa volume");
panicf("invalid pcm alsa volume %d %d", vol_db_l, vol_db_r);
if(format != SND_PCM_FORMAT_S32_LE)
panicf("this function assumes 32-bit sample size");
vol_db_l += 48; /* -42dB .. 0dB => 5dB .. 48dB */