ASoC: SOF: Initial support for IPC4 compress offload #5647

ujfalusi · 2026-01-14T12:00:10Z

Hi,

inital (draft) support for compress offload with IPC4 on Intel platforms (MTL+).

There are still missing features, and few areas to improve, tune, but it works reasonably well and the hope is that the IPC3 compr is still functional.

@dbaluta, if you could be able to test that, we would really appreciate it.

ujfalusi · 2026-01-14T12:26:09Z

I don't see these errors with gcc (GCC) 15.2.1 20251112 locally, hrm.

dbaluta · 2026-01-19T10:38:31Z

Will test this on IMX platforms, but we are only using IPC3 so not sure how much it helps. I'm not working on moving IMX to IPC4 but it will take a while.

Will be back with the results asap.

ujfalusi · 2026-01-19T10:54:47Z

Will test this on IMX platforms, but we are only using IPC3 so not sure how much it helps. I'm not working on moving IMX to IPC4 but it will take a while.

@dbaluta, we want to make sure that we don't break iMX (IPC3) and we are on reverse grounds that we can only test the new IPC4 support.

Will be back with the results asap.

Thank you!

lgirdwood

LGTM, some minor opens, some rebasing/squashing probably needed.

lgirdwood · 2026-01-19T13:52:54Z

sound/soc/soc-pcm.c

+		if (!fe->fe_compr) {
+			be_substream->runtime = fe_substream->runtime;
+		} else {
+			be_substream->runtime = kzalloc(sizeof(*be_substream->runtime), GFP_KERNEL);


any reason why we dont allocate this in the same logic as non compressed i.e. to balance the conditional logic here

The FE is not a PCM, there we don't have runtime at all, but BE is running as a PCM.

lgirdwood · 2026-01-19T14:07:53Z

sound/soc/sof/ipc4-priv.h

+struct sof_ipc4_timestamp_info {
+	struct sof_ipc4_copier *host_copier;
+	struct sof_ipc4_copier *dai_copier;
+	u64 stream_start_offset;


Btw do we subtract any media header from our positions or does cplay need to include this ?

we don't and we don't need to, this is the offset when the first real audio data left the DSP.
The media header is eaten up if it is eaten up by the decoder and it does not matter what the data was.
In compr there is no relation between what the host copies and what is played out.

lgirdwood · 2026-01-19T14:10:14Z

sound/soc/sof/ipc4-compress.c

+
+	spcm->stream[dir].cstream = cstream;
+	spcm->stream[dir].posn.host_posn = 0;
+	spcm->stream[dir].posn.dai_posn = 0;


ok, I assume our dai position will exclude the header as that's not rendered, but host position may include header ? Just wondering if cplay cares.

we don't use the dai_posn in ipc4 and there is no meaning of header in this regard. The DAI is running in PCM mode.

lgirdwood · 2026-01-19T14:12:50Z

sound/soc/sof/ipc4-compress.c

+	/* unprepare and free the list of DAPM widgets */
+	sof_widget_list_unprepare(sdev, spcm, dir);
+
+	cancel_work_sync(&spcm->stream[dir].period_elapsed_work);


should be cancel_work_flush_sync() before we free the widgets ?

hrm, might be better, but this is where the compr has been already stopped and we just report elapsed to ALSA.
I'll take a look.

it is following how normal PCM is handled, I will leave it like this as well.

lgirdwood · 2026-01-19T14:17:46Z

sound/soc/sof/ipc4-compress.c

+	cstream->dma_buffer.dev.type = SNDRV_DMA_TYPE_DEV_SG;
+	cstream->dma_buffer.dev.dev = dev;
+
+	ret = snd_compr_malloc_pages(cstream, crtd->buffer_size);


Btw, is there any size refinement here like with PCMs or is cplay request taken as-is ?

That I'm not sure, but we place a limit on frag size and number in later patch.

The info in get_caps are 'hints' for user space and it can set whatever (cplay does this), so I added checks for buffer_size and number of fragments to avoid invalid configuration.

lgirdwood · 2026-01-19T14:22:28Z

sound/soc/sof/ipc4-compress.c

+	/*
+	 * stream_start_offset is updated to memory window by FW based on
+	 * pipeline statistics and it may be invalid if host query happens before
+	 * the statistics is complete. And it will not change after the first initiailization.


may need a comment on whether header is included or not.

Header has no meaning in here, this is pure PCM data, exactly like normal PCMs, we count the samples played out.

lgirdwood · 2026-01-19T14:27:38Z

sound/soc/sof/ipc4-compress.c

+
+out:
+	caps->direction = cstream->direction;
+	caps->min_fragment_size = 3 * 1024;


based on any particular format ? Maybe worth a comment

gut feeling ;) I will add defines :D

dbaluta · 2026-01-20T21:09:38Z

@ujfalusi Tested this today with sof-dev branch and I get some problems but could be unrelated to the change. Need to check if we have some internal patches not upstreamed.

dbaluta · 2026-01-21T16:48:59Z

@ujfalusi Tested the patches with IMX8MP using IPC3 compress implementation with MP3 and AAC and it works fine. I will add my comments to the code later.

dbaluta · 2026-01-21T16:53:15Z

sound/soc/sof/ipc4-compress.c

+	caps->max_fragment_size = 16 * 1024;
+	caps->min_fragments = 4;
+	caps->max_fragments = 8;
+


I tried to upstream a similar change for IPC3 and got this comments:

https://lists.openwall.net/linux-kernel/2022/01/19/64

So how would we know which formats are supported?

@dbaluta we're adding the capability in the firmware for the decoder to advertise the codecs supported. Please stay tuned for the firmware side patches.

We get the information from fw on what codecs are supported, so this should be fine, it shall cover cases with different fw configurations.

With DPCM when compr is used on FE side, the BE is still running as 'normal' PCM. It is expected that the be_substream->runtime on the BE is not NULL, for example some codec drivers expect to have the substream->runtime valid, to store configuration for example. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

In preparation for adding support for compressed offload support for IPC4, rename the current compress implementation with the IPC3 prefix. Introduce a new field in struct sof_ipc_pcm_ops to save the IPC-specific compressed ops pointer. This should be set when the component driver ops are assigned during SOF device probe. Expose a couple of common functions that will be used by both IPC-specific implementations and rename the compress.c file to ipc3-compress.c Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

These are common functions that will also be needed for the IPC4 compressed support. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

In order to reuse the pipeline triggering logic for compressed support with IPC4, modify the signature of the trigger and hw_free PCM IPC ops so that they can be reused. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

…ng stream After the host DMA IID is released, reset the curr_pos to 0 for a clean start for subsequent stream starts. This is not needed for PCM streams but for compressed streams. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Add new ops in the struct snd_sof_ops for platform-specific ops for compresssed streams. Also, define and set them for the HDA platforms. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Co-developed-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

The SOF_IPC4_MOD_INIT_DATA_ID_MODULE_DATA type within the module_init_ext area is module specific init data. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

…dules Add support for handling init_ext_module_data for process modules, which is going to be used by decoder and encoder type of process mdoules. The support is generic and it can be extended to other type of process modules or other module types than process with a small update of sof_ipc4_add_init_ext_module_data() function. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

…cm.c The support for compressed stream will also need to have access to the same information which is used for delay reporting for DAI data progression tracking. Make the necessary struct and functions to be available and premare them to be called without a valid substream. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

…_params SOF_INFO (id == 35) tuple holds tuple structured information about SOF features. The first entry in SOF_INFO is the SOF_CODEC_INFO (id == 0) which contains information about the supported codecs for decode/encode in the booted firmware. If present in the fw_config payload, make a copy of it and store it sof_ipc4_fw_data->codec_info to be used by the compressed code. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

ujfalusi · 2026-01-22T12:37:08Z

Changes since v2:

rewrite how we report the min fragment size to handle deep buffer on host side

ujfalusi · 2026-01-22T15:05:25Z

Changes since v3:

fix ERROR: modpost: "__udivdi3" [sound/soc/sof/snd-sof.ko] undefined! in x86_32 build

Set and define the compressed ops for IPC4. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Co-developed-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

There is no need to select IPC3 and IPC4 along with INTEL_CNL as INTEL_CNL selects both. Similarly, INTEL_MTL selects IPC4, so there is no need to do that for LNL, PTL and NVL. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Select SOF_COMPRESS for TGL and newer platforms, on Intel devices the compressed support is available with IPC4 only. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Decoder and encoder modules fall under process modules in SOF. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Co-developed-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

ujfalusi · 2026-01-23T08:42:39Z

Changes since v4:
Drop the min_fragment_size storage in sof_compr_stream and remove the use of it in ipc4 code:
It was allocated and stored behind cstream->runtime->private_data, but that pointer is also used by the Intel platform code and it was overtaken on open.
So, (1) we were leaking memory, (2) we were accessing cstream->runtime->private_data data which points to a completely different struct.

It is a surprise that this did not blow up, but it somehow managed to 'work', just that the min_fragment_size turned 0 after the compr_open (as we used the data for read only).

Added a helper to calculate on spot the minimal fragment size instead, it is used only during open operation.

ujfalusi force-pushed the peter/topic/ipc4_compr branch from cea54e7 to c3f4c47 Compare January 14, 2026 14:08

ujfalusi changed the title ~~ASoC: SOF: Initial support for IPCV4 compress offload~~ ASoC: SOF: Initial support for IPC4 compress offload Jan 19, 2026

lgirdwood reviewed Jan 19, 2026

View reviewed changes

dbaluta reviewed Jan 21, 2026

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ujfalusi force-pushed the peter/topic/ipc4_compr branch from c90259d to 7c5f0df Compare January 22, 2026 08:35

ujfalusi and others added 10 commits January 22, 2026 10:36

ASoC: SOF: sof-audio: Expose a couple of functions

5c80069

These are common functions that will also be needed for the IPC4 compressed support. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

ASoC: SOF: ipc4: Add definition of module data in init_ext object type

63216b4

The SOF_IPC4_MOD_INIT_DATA_ID_MODULE_DATA type within the module_init_ext area is module specific init data. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

ujfalusi force-pushed the peter/topic/ipc4_compr branch 2 times, most recently from 228cd7c to a57957e Compare January 22, 2026 12:36

ujfalusi force-pushed the peter/topic/ipc4_compr branch 2 times, most recently from 52d57d7 to f992ff0 Compare January 22, 2026 15:04

ujfalusi force-pushed the peter/topic/ipc4_compr branch from f992ff0 to f16f40d Compare January 23, 2026 08:37

ranj063 and others added 3 commits January 23, 2026 10:37

ASoC: SOF: Add support for IPC4 compressed

cd531c1

Set and define the compressed ops for IPC4. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Co-developed-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

ASoC: SOF: Intel: Kconfig: Select compress support for TGL+ platforms

51a6a49

Select SOF_COMPRESS for TGL and newer platforms, on Intel devices the compressed support is available with IPC4 only. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

ASoC: SOF: Initial support for IPC4 compress offload #5647

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ASoC: SOF: Initial support for IPC4 compress offload #5647

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ujfalusi commented Jan 14, 2026

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