[PATCH v5 0/4] Bluetooth: btintel_pcie: fix D-state transition and PM flows

[Ravindra <ravindra@intel.com>]

This series fixes the suspend/resume path of btintel_pcie.

Patch 1 re-reads the boot stage register before the fallback state check,
so a missed alive interrupt no longer leaves btintel_pcie_set_dxstate()
testing a stale cache and aborting suspend with -EBUSY.

Patch 2 distinguishes S0ix from S3/S4 so the controller is placed in the
correct D-state, and routes .thaw through a normal D0 transition instead
of an unnecessary FLR.

Patch 3 stops treating gp0_received as proof that the requested D-state
transition completed. The flag is set at the top of the GP0 handler,
before the switch on alive_intr_ctxt, so a matched case can return having
changed nothing. The state is now verified against the register, and the
handler's work is completed from the fallback when needed.

Patch 4 clears the GP0 cause with a direct W1C write. The previous
read-modify-write helper wrote zero to GP0, leaving it uncleared, and
could acknowledge unrelated pending causes.

Changes in v5:
- Resend of the full series. v4 4/4 was posted on its own and could not be
  applied by CI, because its context depends on 3/4.
- 4/4: picked up Sergey's Tested-by and Reviewed-by.
- No functional changes since v4.

Changes in v4:
- 3/4: verify the state after the alive interrupt instead of trusting
  gp0_received, keep the flag reset inside the retry loop, complete the
  mbox<->alive handshake, propagate btintel_pcie_start_rx() errors, and
  restore the D3 context when the handler did not record it.
- 4/4: replace the W1C read-modify-write with a direct GP0 write.
- 1/4: corrected the Fixes: tag.

Ravindra (2):
  Bluetooth: btintel_pcie: fix PM flow for S0ix, S3 and S4
  Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

Sergey Lebedev (1):
  Bluetooth: btintel_pcie: verify state after alive interrupt

Vladimir V. Kondratyev (1):
  Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check

 drivers/bluetooth/btintel_pcie.c | 124 ++++++++++++++++++++++---------
 drivers/bluetooth/btintel_pcie.h |   3 +-
 2 files changed, 91 insertions(+), 36 deletions(-)

-- 
2.43.0