For ADSP, only a limited number of FastRPC context banks (CBs) are available. Each CB supports a single session, which means only a few processes can run on ADSP simultaneously. If all sessions are consumed by fastrpc daemons, no session remains available when a user application starts, causing the application to fail.
To work around this, some Device Tree sources set: qcom,nsessions = <5>; which duplicated sessions inline during fastrpc_cb_probe(). Upstream feedback indicated that this policy does not belong in DT and should be handled at the driver level instead. This series removes the per-CB DT-driven duplication and replaces it with a fixed driver-side post-probe step: after of_platform_populate() returns in fastrpc_rpmsg_probe() — once all compute-CB child nodes have been probed and the session array is fully populated — FASTRPC_DUP_SESSIONS (4) copies of the last probed session are appended for the ADSP domain. This keeps the per-CB probe path simple and ensures duplicates are always derived from a stable, fully-initialised session state. The qcom,nsessions binding is deprecated in the same series. Patch [v1]: https://lore.kernel.org/r/[email protected] Signed-off-by: Vinayak Katoch <[email protected]> --- Changes in v2: - Added patch to deprecate the qcom,nsessions dt-binding. - Kept the logic unchanged; only split into two patches. --- Vinayak Katoch (2): dt-bindings: misc: qcom,fastrpc: deprecate qcom,nsessions misc: fastrpc: create duplicate sessions after all CB probing .../devicetree/bindings/misc/qcom,fastrpc.yaml | 2 ++ drivers/misc/fastrpc.c | 30 ++++++++++++---------- 2 files changed, 19 insertions(+), 13 deletions(-) --- base-commit: 97e797263a5e963da3d1e66e743fd518567dfe37 change-id: 20260609-dup-sessions-ea2acaac1994 Best regards, -- Vinayak Katoch <[email protected]>
