Received-SPF: pass (google.com: domain of linux-wireless+bounces-8140-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
From: =?UTF-8?q?Marcin=20=C5=9Alusarz?= <marcin.slusarz@gmail.com>
To: linux-wireless@vger.kernel.org
Cc: =?UTF-8?q?Marcin=20=C5=9Alusarz?= <mslusarz@renau.com>
Subject: wifi: rtw88: 8821CU hangs after some number of power-off/on cycles
Date: Mon, 27 May 2024 19:34:52 +0200
Message-Id: <20240527173454.459264-1-marcin.slusarz@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

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(-)

-- 
2.25.1