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pcm: dmix: fix access to sum-buffer in non-interleaved mixing mode

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When dmix uses non-interleaved mixing mode the offset and step width
to sum_buffer was calculated by using the dmix channels instead of
the slave channels. This leads to audio distortions due to frame
corruption.

example:
- With below configuratio, Do aplay on both device in parallel for
audio distortion

pcm.dmix_2_channels {
        type dmix
        ipc_key 5678293
        ipc_perm 0660
        ipc_gid audio
        bindings [0 1]

        slave {
                pcm "hardware"
                channels 2
                periods  4
                period_time 40000
        }
}

pcm.dmix_1_channels {
        type dmix
        ipc_key 5678293
        ipc_perm 0660
        ipc_gid audio
        bindings [0]

        slave {
                pcm "hardware"
                channels 1
                periods  4
                period_time 40000
        }
}

pcm.hardware {
        type hw
        card 0
        channels 2
        rate 48000
        format S16_LE
}

Signed-off-by: Vijay Palaniswamy <vijay.palaniswamy@in.bosch.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Vijay Palaniswamy 2020-07-23 11:49:10 +05:30 • committed by Takashi Iwai
parent 464c2f8b61
commit 82cb27c165
1 changed files with 4 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

8
src/pcm/pcm_dmix.c
View file

@ -212,10 +212,10 @@ static void mix_areas(snd_pcm_direct_t *dmix,
do_mix_areas(size,
((unsigned char *)dst_areas[dchn].addr + dst_areas[dchn].first / 8) + dst_ofs * dst_step,
((unsigned char *)src_areas[chn].addr + src_areas[chn].first / 8) + src_ofs * src_step,
dmix->u.dmix.sum_buffer + channels * dst_ofs + chn,
dmix->u.dmix.sum_buffer + dmix->shmptr->s.channels * dst_ofs + dchn,
dst_step,
src_step,
channels * sizeof(signed int));
dmix->shmptr->s.channels * sizeof(signed int));
}
}
@ -280,10 +280,10 @@ static void remix_areas(snd_pcm_direct_t *dmix,
do_remix_areas(size,
((unsigned char *)dst_areas[dchn].addr + dst_areas[dchn].first / 8) + dst_ofs * dst_step,
((unsigned char *)src_areas[chn].addr + src_areas[chn].first / 8) + src_ofs * src_step,
dmix->u.dmix.sum_buffer + channels * dst_ofs + chn,
dmix->u.dmix.sum_buffer + dmix->shmptr->s.channels * dst_ofs + dchn,
dst_step,
src_step,
channels * sizeof(signed int));
dmix->shmptr->s.channels * sizeof(signed int));
}
}