On Fri, 05 Sep 2025 11:12:53 +0200, Joris Verhaegen wrote:
The current compress offload timestamping API relies on struct snd_compr_tstamp, whose cumulative counters like copied_total are defined as __u32. On long-running high-resolution audio streams, these 32-bit counters can overflow, causing incorrect availability calculations.
This patch series transitions to a 64-bit safe API to solve the problem while maintaining perfect backward compatibility with the existing UAPI. The pointer operation is reworked to use a new timestamp struct with 64-bit fields for the cumulative counters, named snd_compr_tstamp64. ASoC drivers are updated to use the 64-bit structures. Corresponding ioctls are added to expose them to user-space.
The series is structured as follows:
Patch 1: Updates the pointer op, refactors the core logic and ASoC drivers to use it, and defines the new UAPI structs.
Patch 2: Exposes the SNDRV_COMPRESS_TSTAMP64 ioctl.
Patch 3: Exposes the corresponding SNDRV_COMPRESS_AVAIL64 ioctl.
This series has been tested on a Pixel 9 device. All compress offload use cases, including long-running playback, were verified to work correctly with the new 64-bit API.
Thanks, Joris (George) Verhaegen
Signed-off-by: Joris Verhaegen verhaegen@google.com
Changes in v2:
- Corrected author and Signed-off-by to be consistent (Mark Brown).
Changes in v3:
- Rework pointer op to return 64-bit timestamp, rather than adding a parallel pointer64 op (Charles Keepax, Takashi Iwai, Vinod Koul)
- Bump the protocol version for ABI change (Takashi Iwai)
-Fix linker error on Intel Atom (lkp@intel.com) -Rebase on latest for-next sound tree (Takashi Iwai) -Avoid changing return error code for ioctl (internal) -ASoC: Replace u64 % u32 by do_div(u64, u32) (internal) -ASoC: sprd: change current_data_offset to u64 (internal) Changes in v4: -Fix compiler error on Intel AVS (lkp@intel.com) Changes in v5: -Revert formatting change in compress_offload.c (Vinod Koul)
Joris Verhaegen (3): ALSA: compress_offload: Add 64-bit safe timestamp infrastructure ALSA: compress_offload: Add SNDRV_COMPRESS_TSTAMP64 ioctl ALSA: compress_offload: Add SNDRV_COMPRESS_AVAIL64 ioctl
Applied all patches now to for-next branch for 6.18.
thanks,
Takashi