[PATCH] wifi: ath12k: fix flush failure in recovery scenarios

[Baochen Qiang]

On 4/2/2024 1:01 AM, Jeff Johnson wrote:
> 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 at quicinc.com>
> 
> Do we have QCN9274 test results?
I was thinking this also applies to QCN9274 and should not cause any 
regression because it is quite a straightforward change.

Anyway, more tests more convincing.

Hi Vasanth, could you help with SSR test on this patch? Considering that 
debugfs patches and firmware-assert patch are not included in ath.git, 
you may need to find a way to simulate firmware crash to trigger SSR 
process. Please let me know if you have any issues in that.

>