Hi,
On a platform when the DSP is in use, we cannot select individual links to use or not use the DSP, it is either all or none. On some audio endpoint, like HDMI/DP, it is preferred to not use any processing in DSP to reduce the latency and to allow bytestream pass-through (DTS, DD, etc)
IPC4 introduces a new type of end-to-end connection within the DSP which is using the host DMA and link DMA in a single buffer, working back-to-back, passing the received data without looking at it or trying to understand the format, content.
This mode reduces the latency and allows non PCM streams to be sent from userspace.
The feature is enabled per PCM bases, signalled in topology.
Regards, Peter --- Jyri Sarha (2): ASoC: SOF: ipc4: Add macros for chain-dma message bits ASoC: SOF: ipc4/intel: Add support for chained DMA
Ranjani Sridharan (1): ASoC: SOF: topology: Set pipeline widget before updating IPC structures
include/sound/sof/ipc4/header.h | 29 +++++++ include/uapi/sound/sof/tokens.h | 1 + sound/soc/sof/intel/hda-dai-ops.c | 18 ++++- sound/soc/sof/ipc4-pcm.c | 122 +++++++++++++++++++++++++++++- sound/soc/sof/ipc4-topology.c | 120 ++++++++++++++++++++++++++++- sound/soc/sof/ipc4-topology.h | 2 + sound/soc/sof/topology.c | 48 ++++++------ 7 files changed, 308 insertions(+), 32 deletions(-)