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Date: Tue, 28 May 2024 15:25:39 +0300
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From: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Subject: Re: wifi: rtw88: 8821CU hangs after some number of power-off/on
 cycles
To: =?UTF-8?Q?Marcin_=C5=9Alusarz?= <marcin.slusarz@gmail.com>
Cc: linux-wireless@vger.kernel.org, =?UTF-8?Q?Marcin_=C5=9Alusarz?=
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On 28/05/2024 13:42, Marcin Ślusarz wrote:
> pon., 27 maj 2024 o 20:43 Bitterblue Smith <rtl8821cerfe2@gmail.com> napisał(a):
>>
>> On 27/05/2024 20:34, Marcin Ślusarz wrote:
>>> From: Marcin Ślusarz <mslusarz@renau.com>
>>>
>>> If I don't connect to any Wifi network, after around 10 minutes, the device
>>> hangs with endless spamming of:
>>> rtw_8821cu 1-1:1.2: rtw_usb_reg_sec: reg 0x4e0, usb write 1 fail, status: -71
>>> killing both Wifi and Bluetooth part of the device.
>>>
>>> On arm, just leaving the wifi device unconnected kills it in up to 20 minutes.
>>> If I keep restarting wpa_supplicant I can trigger it within a minute.
>>> Looping "ifconfig wlan0 down; ifconfig wlan0 up" also triggers it within a minute.
>>>
>>> On x86_64 system the only way I could trigger this was via ifconfig loop,
>>> but it took 3 hours and 20 minutes to do it.
>>>
>>> The only thing that can "fix" the device is replugging it.
>>>
>>> I found out that the reason for those hangs is a power-off+on sequence that's
>>> triggered by the above steps.
>>>
>>> Disabling power-off for that chip "fixes" the issue. The patches below
>>> implement that, but I'm not seriously proposing them for merging.
>>>
>>> Marcin Ślusarz (2):
>>>   wifi: rtw88: use RTW_FLAG_RUNNING for deciding whether to enter/leave
>>>     IPS
>>>   wifi: rtw88: disable power offs for 8821C
>>>
>>>  drivers/net/wireless/realtek/rtw88/main.c | 14 ++++++++------
>>>  drivers/net/wireless/realtek/rtw88/ps.c   |  4 ++--
>>>  2 files changed, 10 insertions(+), 8 deletions(-)
>>>
>>
>> The first patch alone doesn't fix it?
> 
> The first patch exists only to make the second patch work.
> Without the first one, rtw_enter_ips will perform all actions except actually
> doing the power off, which clears the POWERON flag.
> After that, rtw_leave_ips will happily return early success without actually
> undoing the stuff that rtw_enter_ips did (like canceling all work_structs).

I see.

I wonder if it's really the chip that has a problem, or rtw88?
Can you try your ifconfig loop with the other driver?
https://github.com/morrownr/8821cu-20210916/