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Message-ID: <dc3ee4aa-6fce-44d3-9095-b8b2846e1f4b@quicinc.com>
Date: Mon, 1 Apr 2024 10:01:50 -0700
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Subject: Re: [PATCH] wifi: ath12k: fix flush failure in recovery scenarios
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To: Baochen Qiang <quic_bqiang@quicinc.com>, <ath12k@lists.infradead.org>
CC: <linux-wireless@vger.kernel.org>
References: <20240329015630.3019-1-quic_bqiang@quicinc.com>
From: Jeff Johnson <quic_jjohnson@quicinc.com>
In-Reply-To: <20240329015630.3019-1-quic_bqiang@quicinc.com>
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On 3/28/2024 6:56 PM, Baochen Qiang wrote:
> Commit eaf9f17b861b ("wifi: ath12k: relocate ath12k_dp_pdev_pre_alloc()
> call") moves ath12k_dp_pdev_pre_alloc() from ath12k_core_start() to
> ath12k_mac_allocate(), resulting in ath12k_mac_flush() failure in
> recovery scenarios:
> 
> [ 6849.684104] ath12k_pci 0000:04:00.0: pdev 0 successfully recovered
> [ 6854.907320] ath12k_pci 0000:04:00.0: failed to flush transmit queue 0
> [ 6860.027353] ath12k_pci 0000:04:00.0: failed to flush transmit queue 0
> [ 6865.143385] ath12k_pci 0000:04:00.0: failed to flush transmit queue 0
> 
> This is because, with ath12k_dp_pdev_pre_alloc() moved to ath12k_mac_allocate(),
> dp->num_tx_pending is not reset due to ATH12K_FLAG_REGISTERED set in
> recovery scenarios.
> 
> So a possible fix would be to reset that counter at some proper point,
> just like the old design. But considering that the counter tracks number
> of packets pending to be freed or returned to mac80211, forcefully reset
> it might make it hard to expose some real issues. For example if somehow
> ath12k fails to free/return some TX packets, we don't know that because
> no warnings any more.
> 
> That is to say we should not reset that counter during recovery (which is
> already done due to above commit), instead should decrease it each time
> a packet is freed/returned. Currently almost each related function has
> this logic implemented, except ath12k_dp_cc_cleanup(). So add the same
> there to fix this issue.
> 
> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4
> 
> Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>

Do we have QCN9274 test results?