iwl_mvm_rx_crypto() does not handle IWL_RX_MPDU_STATUS_SEC_UNKNOWN
explicitly in the non-AMPDU path: the switch's default case fires
"Unhandled alg: 0x71b" for what the firmware documents as a benign
condition (a cipher class not enumerated in the RX status field, or
frames arriving before key install).  On a Meteor Lake laptop with
an AX210 this produced 152 warnings across ~43.5 hours of normal
use; net_ratelimit spaced them out but did not silence them.  The
AMPDU sibling path at the top of the function already handles this
status explicitly.

Add an explicit SEC_UNKNOWN case that breaks to the final return 0
(passing the frame undecrypted to mac80211, matching the default's
effective behavior), with a dev_info_once() so the condition stays
observable at default log levels without per-frame spam, and an
IWL_DEBUG_DROP per occurrence mirroring the AMPDU handler.  Behavior
for every other status value is unchanged.

Link: https://lore.kernel.org/all/0e1a890d2896791d7291f0174cc0e96832d7ed33.camel@intel.com/ (local)
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Mike Bommarito <redacted>
---
Historical context (for reviewers, not the changelog)

The same warning was reported on Intel 9260 in 2019 [1].  Emmanuel
Grumbach acknowledged then that "this print is harmless really",
attributed it to a deprecated firmware flag, and suggested two
fixes: "remove the warning message entirely or limit it to unicast
packets only -- this has been merged in our internal repository and
it will be upstreamed following the regular process."  The unicast
restriction is now in tree (the default case guards on
!is_multicast_ether_addr() && net_ratelimit()), but the
remove-the-warning half never landed upstream.

This patch is the narrower of Grumbach's two suggestions: only
IWL_RX_MPDU_STATUS_SEC_UNKNOWN is special-cased, the existing
default-case warning is preserved for genuinely unknown status
values.

Test data

Pre-patch baseline on Framework Laptop 13 (Intel Core Ultra 5 125H,
AX210, Linux 7.1-rc4): 152 "Unhandled alg: 0x71b" entries in dmesg
across ~43.5 hours of mixed use, plus a burst of three within 70 ms
during a single re-association:

    [162152.782317] iwlwifi 0000:aa:00.0: Unhandled alg: 0x71b
    [162152.813440] iwlwifi 0000:aa:00.0: Unhandled alg: 0x71b
    [162152.844499] iwlwifi 0000:aa:00.0: Unhandled alg: 0x71b

Status decoding: 0x71b & 0x700 == SEC_UNKNOWN; low bits are
informational and vary between frames.

Post-patch: module rebuilt + reloaded.  Triggered scans and
nmcli reconnect cycles until a SEC_UNKNOWN frame was received.
The new switch case fired its dev_info_once exactly once:

    iwlwifi 0000:aa:00.0: RX SEC_UNKNOWN (status=0x707)

Zero "Unhandled alg" warnings observed during the same window.
A CONFIG_IWLWIFI_DEBUG=y build with IWL_DL_DROP enabled would
additionally show one IWL_DEBUG_DROP per qualifying frame; the
test kernel had CONFIG_IWLWIFI_DEBUG=n so those entries are absent
but the dev_info_once carries the per-controller signature.

 drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
index 7f0b4f5daa21..f36e99c90ee3 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c

@@ -494,6 +494,19 @@ static int iwl_mvm_rx_crypto(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 		return 0;
 	case RX_MPDU_RES_STATUS_SEC_CMAC_GMAC_ENC:
 		break;
+	case IWL_RX_MPDU_STATUS_SEC_UNKNOWN:
+		/*
+		 * Firmware-indicated unknown cipher; the AMPDU case is
+		 * already handled at the top of this function.  For
+		 * non-AMPDU frames this is valid (cipher not enumerated
+		 * by the RX status field, or frame before key install).
+		 * Pass undecrypted to mac80211.
+		 */
+		dev_info_once(mvm->dev,
+			      "RX SEC_UNKNOWN (status=0x%x)\n", status);
+		IWL_DEBUG_DROP(mvm,
+			       "RX SEC_UNKNOWN (status=0x%x)\n", status);
+		break;
 	default:
 		/*
 		 * Sometimes we can get frames that were not decrypted

-- 
2.53.0