[PATCH ath-next v3 3/9] wifi: ath11k: report the pending tx MSDU count in soc_dp_stats

[Julius Bairaktaris]

ar->dp.num_tx_pending counts the MSDUs the hardware has not completed
yet, and is used to wait for the transmit path to drain. It is never
shown.

soc_dp_stats can therefore say when the transmit path overflowed - TCL ring
full, misc transmit failures - and not how deep it is at this instant. The
bound those counters report against is the tx descriptor idr, one entry
short of DP_TX_IDR_SIZE per ring, which is large enough that occupancy
rather than exhaustion is what characterises the path under load.

Print it per radio, beside the failure counters it complements.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.9.0.1-02146-QCAHKSWPL_SILICONZ-1
Assisted-by: Claude:claude-opus-5
Signed-off-by: Julius Bairaktaris <julius at bairaktaris.de>
---
 drivers/net/wireless/ath/ath11k/debugfs.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/wireless/ath/ath11k/debugfs.c b/drivers/net/wireless/ath/ath11k/debugfs.c
index 70922612d3fb..9dc586b68136 100644
--- a/drivers/net/wireless/ath/ath11k/debugfs.c
+++ b/drivers/net/wireless/ath/ath11k/debugfs.c
@@ -714,6 +714,18 @@ static ssize_t ath11k_debugfs_dump_soc_dp_stats(struct file *file,
 			 "\nMisc Transmit Failures: %d\n",
 			 atomic_read(&soc_stats->tx_err.misc_fail));
 
+	/* What the hardware still owes a completion for. The counters above say
+	 * when the transmit path overflowed; none of them says how deep it is.
+	 */
+	len += scnprintf(buf + len, size - len, "\nPending Tx MSDUs:\n");
+	for (i = 0; i < ab->num_radios; i++) {
+		struct ath11k *ar = ab->pdevs[i].ar;
+
+		if (ar)
+			len += scnprintf(buf + len, size - len, "radio%d: %d\n",
+					 i, atomic_read(&ar->dp.num_tx_pending));
+	}
+
 	len += ath11k_debugfs_dump_soc_ring_bp_stats(ab, buf + len, size - len);
 
 	if (len > size)
-- 
2.53.0