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Message-ID: <514da0bc-f9f6-41fb-9e3e-72677394695f@quicinc.com>
Date: Thu, 18 Apr 2024 10:52:53 -0700
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Subject: Re: [PATCH] wifi: ath12k: Fix Tx Completion Ring(WBM2SW) Setup
 Failure
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From: Jeff Johnson <quic_jjohnson@quicinc.com>
To: Nithyanantham Paramasivam <quic_nithp@quicinc.com>,
        <ath12k@lists.infradead.org>
CC: <linux-wireless@vger.kernel.org>
References: <20240409190922.4180631-1-quic_nithp@quicinc.com>
 <c5dec609-493a-4246-b006-aa905edfdac3@quicinc.com>
In-Reply-To: <c5dec609-493a-4246-b006-aa905edfdac3@quicinc.com>
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On 4/10/2024 1:25 PM, Jeff Johnson wrote:
> On 4/9/2024 12:09 PM, Nithyanantham Paramasivam wrote:
>> We observe intermittent ping failures from the access point (AP) to
>> station (STA) in any mode(AP-STA or Mesh) configured. Specifically,
>> the transmission completion status is not received at Tx completion
>> ring id-4(WBM2SW ring4) for the packets transmitted via TCL DATA
>> ring id-3. This prevents freeing up Tx descriptors and leads
>> to buffer exhaustion.
>>
>> Currently, during initialization of the WBM2SW ring, we are directly
>> mapping the ring number to the ring mask to obtain the ring mask
>> group index. This approach is causing setup failures for WBM2SW
>> ring-4. Similarly, during runtime, when receiving incoming
>> transmission completion status, the validation of the ring number by
>> mapping the interrupted ring mask. This is resulting in
>> validation failure. Thereby preventing entry into the completion
>> handler(ath12k_dp_tx_completion_handler()).
>>
>> The existing design assumed that the ring numbers would always be
>> sequential and could be directly mapped with the ring mask. However,
>> this assumption does not hold true for WBM2SW ring-4. Therefore,
>> modify the design such that, instead of mapping the ring number,
>> the ring ID is mapped with the ring mask.
>>
>> According to this design:
>> 1. During initialization of the WBM2SW ring, mapping the ring ID
>> to the ring mask will ensure obtaining the correct ring mask group
>> ID.
>> 2. During runtime, validating the interrupted ring mask group ID
>> within the transmission completion group is sufficient. This
>> approach allows the ring ID to be derived from the interrupted ring
>> mask and enables entry into the completion handler.
>>
>> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
>>
>> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
>> Signed-off-by: Nithyanantham Paramasivam <quic_nithp@quicinc.com>
> Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
> 
> 
Please remove my Acked-by.

I've bisected a kernel crash on my laptop to this patch