linux-kernel - [PATCH ath-next 3/3] wifi: ath12k: downgrade log level for CE buffer enqueue failure

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Message-Id: <20250815-ath-dont-warn-on-ce-enqueue-fail-v1-3-f955ddc3ba7a@oss.qualcomm.com>
Date: Fri, 15 Aug 2025 09:44:58 +0800
From: Baochen Qiang <baochen.qiang@....qualcomm.com>
To: Jeff Johnson <jjohnson@...nel.org>, Kalle Valo <kvalo@...nel.org>,
        Carl Huang <quic_cjhuang@...cinc.com>,
        Karthikeyan Periyasamy <quic_periyasa@...cinc.com>,
        P Praneesh <quic_ppranees@...cinc.com>,
        Sriram R <quic_srirrama@...cinc.com>
Cc: linux-wireless@...r.kernel.org, ath11k@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Jeff Johnson <jeff.johnson@....qualcomm.com>,
        Balamurugan Selvarajan <quic_bselvara@...cinc.com>,
        Ramya Gnanasekar <quic_rgnanase@...cinc.com>,
        ath12k@...ts.infradead.org,
        Baochen Qiang <baochen.qiang@....qualcomm.com>
Subject: [PATCH ath-next 3/3] wifi: ath12k: downgrade log level for CE
 buffer enqueue failure

There are two rings involved in the Copy Engine (CE) receive path
handling, the CE status (STS) ring and the CE destination (DST) ring.
Each time CE hardware needs to send an event (e.g. WMI event) to host,
CE hardware finds a buffer (to which the tail pointer (TP) points) in
DST ring and fills it with payload, then hardware fills meta data in
STS ring and fires interrupt to host. Please note the TP of DST ring is
expected to be advanced by CE hardware before interrupting host. While
handling the interrupt, host finds that DST ring buffers are used hence
increases rx_buf_needed to record the number of buffers to be replenished.
Note before that, host compares TP and head pointer (HP) of DST ring to
see if there is available space. Normally rx_buf_needed simply equals
available space. But sometimes CE hardware doesn't (for whatever reason)
update TP timely, making the comparison fails, then enqueue is cancelled
and a warning is logged.

However even enqueue fails this time, rx_buf_needed still records the
numbers of needed buffers. Later when TP gets updated correctly, the
missing buffer will be eventually replenished. And there is no doubt on
the late update, it always comes (or lots of such warnings should be seen).

Since this won't cause any functional issue, downgrade logging level to
avoid misleading.

Compile tested only.

Signed-off-by: Baochen Qiang <baochen.qiang@....qualcomm.com>
---
 drivers/net/wireless/ath/ath12k/ce.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/ce.c b/drivers/net/wireless/ath/ath12k/ce.c
index c5aadbc6367ce0d18080bb0e15a88d3ddf2e34ff..9a63608838ace31587691dd53c1d4aa8f081cb6f 100644
--- a/drivers/net/wireless/ath/ath12k/ce.c
+++ b/drivers/net/wireless/ath/ath12k/ce.c
@@ -392,7 +392,8 @@ static int ath12k_ce_rx_post_pipe(struct ath12k_ce_pipe *pipe)

 		ret = ath12k_ce_rx_buf_enqueue_pipe(pipe, skb, paddr);
 		if (ret) {
-			ath12k_warn(ab, "failed to enqueue rx buf: %d\n", ret);
+			ath12k_dbg(ab, ATH12K_DBG_CE, "failed to enqueue rx buf: %d\n",
+				   ret);
 			dma_unmap_single(ab->dev, paddr,
 					 skb->len + skb_tailroom(skb),
 					 DMA_FROM_DEVICE);

-- 
2.25.1