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Message-ID: <a0e50b38-cd84-4798-8224-b8a80f148a9f@quicinc.com>
Date: Thu, 9 May 2024 09:01:09 -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>
 <514da0bc-f9f6-41fb-9e3e-72677394695f@quicinc.com>
 <b96ae3ec-44e0-42e1-8b3f-89144f01c272@quicinc.com>
In-Reply-To: <b96ae3ec-44e0-42e1-8b3f-89144f01c272@quicinc.com>
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On 5/9/2024 7:39 AM, Jeff Johnson wrote:
> On 4/18/2024 10:52 AM, Jeff Johnson wrote:
>> 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
> 
> While debugging my crash I've determined the issue isn't with this patch, so
> restore my:
> 
> Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
> 
> /jeff
> 
OK, I got confused between testing public patches & internal patches. It turns
out this version actually does have an issue, and there is a respin coming.

So reinstate the NAK on this version.