netdev - Re:Re: [PATCH] wifi: rtl8xxxu: fix authentication timeout due to incorrect RCR value

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Date:   Fri, 28 Apr 2023 12:30:47 +0800 (CST)
From:   "Yun Lu" <luyun_611@....com>
To:     "Bitterblue Smith" <rtl8821cerfe2@...il.com>
Cc:     Jes.Sorensen@...il.com, kvalo@...nel.org, davem@...emloft.net,
        edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org
Subject: Re:Re: [PATCH] wifi: rtl8xxxu: fix authentication timeout due to
 incorrect RCR value

At 2023-04-28 01:01:06, "Bitterblue Smith" <rtl8821cerfe2@...il.com> wrote:
>On 27/04/2023 05:05, Yun Lu wrote:
>> From: Yun Lu <luyun@...inos.cn>
>> 
>> When using rtl8192cu with rtl8xxxu driver to connect wifi, there is a
>> probability of failure, which shows "authentication with ... timed out".
>> Through debugging, it was found that the RCR register has been inexplicably
>> modified to an incorrect value, resulting in the nic not being able to
>> receive authenticated frames.
>> 
>> To fix this problem, add regrcr in rtl8xxxu_priv struct, and store
>> the RCR value every time the register is writen, and use it the next
>> time the register need to be modified.
>> 
>
>Can this bug be reproduced easily? Is it always the same bits which
>are mysteriously cleared from REG_RCR?

On the device(EDIMAX EW-7822UAn) we used, it can be reproduced easily.
And the changed bits is not always the same, as the log shows in my reply
to Larry.
It seems that the nic will modify the value of this register itself? I guess it.

Thanks.