There are two sequence number fields per GSP RPC message: an outer
transport-level seqNum in the GSP_MSG_QUEUE_ELEMENT header, and an
inner rpc.sequence in the rpc_message_header_v. Nova was leaving the
inner field at zero for all sends and had no way to tell async events
apart from command responses on the receive side.
This led to really confusing log messages and code as well.
Patch 1 fixes the wire-level sequence numbers to match Open RM.
Patch 2 updates the debug logging to show the message classification.
This is "GSP future friendly", in that it is written with GSP seq number
handling plans in mind. I'm including Maneet Singh to help poke holes in
that claim.
Example output:
GSP RPC: async send: seq# 0, function=GSP_SET_SYSTEM_INFO, length=0x3f0
GSP RPC: async send: seq# 1, function=SET_REGISTRY, length=0xc5
GSP RPC: async received: seq# 0, function=LOCKDOWN_NOTICE, length=0x51
GSP RPC: async received: seq# 17, function=INIT_DONE, length=0x50
GSP RPC: send: seq# 2, function=GET_GSP_STATIC_INFO, length=0x6c8
GSP RPC: response received: seq# 2, function=GET_GSP_STATIC_INFO, length=0x6c8
With the inner rpc.sequence now set correctly, GSP echoes back the
CPU's sequence number in command responses, so the response seq#
matches the send seq#.
This is based on the Feb 5, 2026 linux-next: commit 9845cf73f7db ("Add
linux-next specific files for 20260205").
Also, this should be applied on top of Eliot Courtney's command queue
ring buffer fix series [1]. Without it, I was seeing slice bounds panics
in driver_read_area().
And finally, because I expect this to go in likely after Blackwell (or
not?), I've based it on that. So putting all that together, there is
a branch with [1] and Blackwell and this series, here for convenience:
https://github.com/johnhubbard/linux/tree/nova-core-gsp-rpc-seq-numbers-v0
[1]
https://lore.kernel.org/r/[email protected]
Cc: Maneet Singh <[email protected]>
John Hubbard (2):
gpu: nova-core: fix GSP RPC send sequence numbers to match Open RM
gpu: nova-core: improve GSP RPC debug logging with message
classification
drivers/gpu/nova-core/gsp/boot.rs | 6 +-
drivers/gpu/nova-core/gsp/cmdq.rs | 84 +++++++++++++++++++++------
drivers/gpu/nova-core/gsp/commands.rs | 2 +
drivers/gpu/nova-core/gsp/fw.rs | 35 +++++++++--
4 files changed, 104 insertions(+), 23 deletions(-)
base-commit: 6738f143db92177013a500fbea5edd771c173bf9
--
2.53.0
