From 6de6e1459de28bef919b869ee757474c615cb787 Mon Sep 17 00:00:00 2001 From: Dana Conrad Date: Mon, 9 Aug 2021 19:22:52 -0500 Subject: [PATCH] Eros Q Hosted: Apply DC Bias to PCM Data Similar to the native port, the hosted port benefits from adding a -1 dc bias to the PCM data. This prevents almost all clicking artifacts. Change-Id: Ic6378716774b6d88df23c476e2ef54d49f33dc72 --- firmware/export/erosqlinux_codec.h | 2 ++ firmware/target/hosted/pcm-alsa.c | 9 +++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/firmware/export/erosqlinux_codec.h b/firmware/export/erosqlinux_codec.h index b6ab58fa74..2ed1ae11cf 100644 --- a/firmware/export/erosqlinux_codec.h +++ b/firmware/export/erosqlinux_codec.h @@ -3,6 +3,8 @@ #define AUDIOHW_CAPS (LINEOUT_CAP) +#define PCM_DC_OFFSET_VALUE -1 + AUDIOHW_SETTING(VOLUME, "dB", 0, 2, -74, 0, -40) //#define AUDIOHW_NEEDS_INITIAL_UNMUTE diff --git a/firmware/target/hosted/pcm-alsa.c b/firmware/target/hosted/pcm-alsa.c index 13ebbbcbeb..68002d8158 100644 --- a/firmware/target/hosted/pcm-alsa.c +++ b/firmware/target/hosted/pcm-alsa.c @@ -68,6 +68,11 @@ #warning "MIX_FRAME_SAMPLES <1024 may cause dropouts!" #endif +/* PCM_DC_OFFSET_VALUE is a workaround for eros q hardware quirk */ +#if !defined(PCM_DC_OFFSET_VALUE) +# define PCM_DC_OFFSET_VALUE 0 +#endif + static const snd_pcm_access_t access_ = SND_PCM_ACCESS_RW_INTERLEAVED; /* access mode */ #if defined(HAVE_ALSA_32BIT) static const snd_pcm_format_t format = SND_PCM_FORMAT_S32_LE; /* sample format */ @@ -359,8 +364,8 @@ static bool copy_frames(bool first) sample_t *sample_ptr = &frames[2*(period_size-frames_left)]; for (int i = 0; i < nframes; i++) { - *sample_ptr++ = *pcm_ptr++ * dig_vol_mult_l; - *sample_ptr++ = *pcm_ptr++ * dig_vol_mult_r; + *sample_ptr++ = (*pcm_ptr++ * dig_vol_mult_l) + PCM_DC_OFFSET_VALUE; + *sample_ptr++ = (*pcm_ptr++ * dig_vol_mult_r) + PCM_DC_OFFSET_VALUE; } } else