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Subject: Re: [PATCHv3] wifi: ath11k: skip status ring entry processing
From: Meiyong Yu <meiyong.yu@126.com>
In-Reply-To: <c8812227-ae90-4bbe-9fd3-425b61e36838@quicinc.com>
Date: Sun, 28 Apr 2024 20:54:42 +0800
Cc: Tamizh Chelvam Raja <quic_tamizhr@quicinc.com>,
 ath11k@lists.infradead.org,
 linux-wireless@vger.kernel.org,
 Venkateswara Naralasetty <quic_vnaralas@quicinc.com>,
 kernel test robot <lkp@intel.com>
Content-Transfer-Encoding: quoted-printable
Message-Id: <A8B8371F-2FF4-45C7-9BEA-BE7FD5CA288F@126.com>
References: <20240427091248.2013946-1-quic_tamizhr@quicinc.com>
 <c8812227-ae90-4bbe-9fd3-425b61e36838@quicinc.com>
To: Jeff Johnson <quic_jjohnson@quicinc.com>


> On Apr 28, 2024, at 6:46 AM, Jeff Johnson <quic_jjohnson@quicinc.com> =
wrote:
>=20
> On 4/27/2024 2:12 AM, Tamizh Chelvam Raja wrote:
>> From: Venkateswara Naralasetty <quic_vnaralas@quicinc.com>
>>=20
>> 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.
>>=20
>> 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.
>>=20

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.

>> 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.
>>=20
>> 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.
>>=20
>> To avoid this issue call ath11k_hal_srng_src_next_peek() instead of
>> calling ath11k_hal_srng_src_peek().
>>=20
>> Tested-on: IPQ5018 hw1.0 AHB =
WLAN.HK.2.6.0.1-00861-QCAHKSWPL_SILICONZ-1
>>=20
>> Reported-by: kernel test robot <lkp@intel.com>
>> Closes: =
https://lore.kernel.org/oe-kbuild-all/202303281719.CvnPkOiK-lkp@intel.com/=

>=20
> 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
>=20
>> 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>
>>=20
>> 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 +
>=20
> 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
>=20