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Date: Mon, 29 Apr 2024 12:39:44 +0530
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Subject: Re: [PATCHv3] wifi: ath11k: skip status ring entry processing
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To: Meiyong Yu <meiyong.yu@126.com>, Jeff Johnson <quic_jjohnson@quicinc.com>
CC: <ath11k@lists.infradead.org>, <linux-wireless@vger.kernel.org>,
        Venkateswara Naralasetty <quic_vnaralas@quicinc.com>,
        kernel test robot
	<lkp@intel.com>
References: <20240427091248.2013946-1-quic_tamizhr@quicinc.com>
 <c8812227-ae90-4bbe-9fd3-425b61e36838@quicinc.com>
 <A8B8371F-2FF4-45C7-9BEA-BE7FD5CA288F@126.com>
 <22DBEF03-83C8-460D-AF50-E1DE0038C072@126.com>
From: Tamizh Chelvam Raja <quic_tamizhr@quicinc.com>
In-Reply-To: <22DBEF03-83C8-460D-AF50-E1DE0038C072@126.com>
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On 4/28/2024 6:32 PM, Meiyong Yu wrote:
> 
> 
>> On Apr 28, 2024, at 8:54 PM, Meiyong Yu <meiyong.yu@126.com> wrote:
>>
>>
>>
>>> On Apr 28, 2024, at 6:46 AM, Jeff Johnson <quic_jjohnson@quicinc.com> wrote:
>>>
>>> On 4/27/2024 2:12 AM, Tamizh Chelvam Raja wrote:
>>>> From: Venkateswara Naralasetty <quic_vnaralas@quicinc.com>
>>>>
>>>> If STATUS_BUFFER_DONE is not set for a monitor status ring entry,
>>>> we don't process the status ring until STATUS_BUFFER_DONE set
>>>> for that status ring entry.
>>>>
>>>> During LMAC reset it may happen that hardware will not write
>>>> STATUS_BUFFER_DONE tlv in status buffer, in that case we end up
>>>> waiting for STATUS_BUFFER_DONE leading to backpressure on monitor
>>>> status ring.
>>>>
>>
>> Can you known the LMAC reset event, if you can known, you can set all the ring entry
>> status  to done after reset is done, and the logic of code will be more clear.
>>
Host unaware of this event as this is internal to hardware. And as per the suggestion we are  reaping next entry
and proceeding further on this.
> 
> If sene of the LMAC reset event is asynchronous, You can do this:
>   1) when  LMAC init than set  a value to the new add global variabe lmac_life_cycle_id
>   2) before add tlv to ring, set lmac_life_cycle_id to tlv
>   3) when LMAC reset event is trigger, increase the value of lmac_life_cycle_id 
>  4) when get the status of tlv in ring(must delay for same period to ensure the real send ring is already send), 
>     check the value  lmac_life_cycle_id  in tlv, if it smaller than the  global one set tlv status to DONE 
> 
> 
>>>> To fix the issue, when HP(Head Pointer) + 1 entry is peeked and if DMA
>>>> is not done and if HP + 2 entry's DMA done is set,
>>>> replenish HP + 1 entry and start processing in next interrupt.
>>>> If HP + 2 entry's DMA done is not set, poll onto HP + 1 entry DMA
>>>> done to be set.
>>>>
>>>> Also, during monitor attach HP points to the end of the ring and
>>>> TP(Tail Pointer) points to the start of the ring.
>>>> Using ath11k_hal_srng_src_peek() may result in processing invalid buffer
>>>> for the very first interrupt. Since, HW starts writing buffer from TP.
>>>>
>>>> To avoid this issue call ath11k_hal_srng_src_next_peek() instead of
>>>> calling ath11k_hal_srng_src_peek().
>>>>
>>>> Tested-on: IPQ5018 hw1.0 AHB WLAN.HK.2.6.0.1-00861-QCAHKSWPL_SILICONZ-1
>>>>
>>>> Reported-by: kernel test robot <lkp@intel.com>
>>>> Closes: https://lore.kernel.org/oe-kbuild-all/202303281719.CvnPkOiK-lkp@intel.com/
>>>
>>> I believe these are misleading. LKP didn't find the problem you are fixing, it
>>> found a problem in the implementation of the patch.
>>> So I would move these below the "---" so the LKP knows the issue it found is
>>> fixed, but the git history isn't itself isn't misleading
>>>
>>>> Signed-off-by: Venkateswara Naralasetty <quic_vnaralas@quicinc.com>
>>>> Co-developed-by: Tamizh Chelvam Raja <quic_tamizhr@quicinc.com>
>>>> Signed-off-by: Tamizh Chelvam Raja <quic_tamizhr@quicinc.com>
>>>> ---
>>>> v3:
>>>> * Rebased on top of ToT
>>>> v2:
>>>> * Fixed compilation warning Reported-by: kernel test robot <lkp@intel.com>
>>>>
>>>> drivers/net/wireless/ath/ath11k/dp_rx.c | 88 ++++++++++++++++++++++---
>>>> drivers/net/wireless/ath/ath11k/hal.c   | 14 ++++
>>>> drivers/net/wireless/ath/ath11k/hal.h   |  2 +
>>>
>>> My Qualcomm Innovation Center copyright checker reports:
>>> drivers/net/wireless/ath/ath11k/dp_rx.c copyright missing 2024
>>> drivers/net/wireless/ath/ath11k/hal.c copyright missing 2024
>>>
>>
> 


-- 
Tamizh