QCS6490 RB3 Gen 2: CDSP remoteproc intermittently fails to boot (`can't start rproc cdsp: -110`)

[koenkooi]

On the QCS6490 RB3 Gen 2 Vision Kit, a boot failed to start the CDSP remote processor. This leaves no /dev/fastrpc-cdsp* devices, while ADSP does remain available.

A subsequent boot did give me a cdsp, so it' intermittent.

Failing boot

• Board: QCS6490 RB3 Gen 2 Vision Kit (qcs6490-rb3gen2)
• qcom-deb-images daily: 34337487309-1
• qcom-deb-images commit: 262b346fe5970c5d00b2a97944790be57a4d6106
• Kernel: 7.2.0-rc7-g011a82096bee
• Kernel build timestamp: Wed Sep 9 09:53:45 UTC 2026
• Test run: https://github.com/qualcomm-linux/aiml-container-test/actions/runs/34470087069

Relevant boot log:

[    0.000000] OF: reserved mem: ... cdsp-secure-heap@81800000
[    0.000000] OF: reserved mem: ... cdsp@88900000

[   21.772486] qcom,fastrpc 3700000.remoteproc:glink-edge.fastrpcglink-apps-dsp.-1.-1: No session available
[   21.783727] qcom,fastrpc 3700000.remoteproc:glink-edge.fastrpcglink-apps-dsp.-1.-1: No session available
...

[   26.079757] qcom_q6v5_pas a300000.remoteproc: start timed out
[   27.236108] remoteproc remoteproc3: can't start rproc cdsp: -110
[   32.479778] qcom_q6v5_pas a300000.remoteproc: start timed out
[   33.638414] remoteproc remoteproc3: can't start rproc cdsp: -110
[   33.647842] remoteproc remoteproc3: Boot failed: -110

After boot:

INFO: Found 0 nodes for pattern /dev/fastrpc-cdsp*
INFO: Found 1 nodes for pattern /dev/fastrpc-adsp*

Comparison with a successful boot

An earlier successful boot on the same board exposed two CDSP FastRPC nodes and successfully ran CDSP TensorFlow Lite workloads.

• CDSP-present daily: 33285461700-1

• CDSP-present commit: 025787822e58ff6f7485405cc733bd33ceb74080

• Kernel: 7.2.0-rc7-g011a82096bee, built Aug 30, 2026

• CDSP bring-up:

  [ 19.181174] qcom_q6v5_pas a300000.remoteproc: Handover signaled, but it already happened
  [ 19.189623] qcom_q6v5_pas a300000.remoteproc: Handover signaled, but it already happened
  INFO: Found 2 nodes for pattern /dev/fastrpc-cdsp*
  INFO: Found 1 nodes for pattern /dev/fastrpc-adsp*

The kernel release and relevant command-line flags are the same in both boots:

clk_ignore_unused pd_ignore_unused audit=0 deferred_probe_timeout=30