MIME-Version: 1.0
From:   "Fuzzey, Martin" <martin.fuzzey@flowbird.group>
Date:   Fri, 26 Nov 2021 11:20:39 +0100
Message-ID: <CANh8QzxPWN7uHGYaU1rpMF+J=vqjbLs+o325UcQc54+6OWiVHw@mail.gmail.com>
Subject: [REGRESSION] mwifiex: mwifiex_get_chan_type noisy and possibly
 incorrect after kernel upgrade
To:     linux-wireless@vger.kernel.org
Cc:     Sharvari Harisangam <sharvari.harisangam@nxp.com>,
        Ganapathi Bhat <ganapathi017@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi,

After upgrading an old system using a SD8787 wifi module from kernel
4.4 to 5.4.143 I started getting error messages in the logs
    mwifiex_sdio mmc2:0001:1: CMD_RESP: cmd 0x23f error, result=0x2

The same error occurs on 5.15 too.
With Android userspace this occurs every 3 seconds but can be
reproduced with a Linux userspace too using the wpa_cli "signal_poll"
command
(Android polls that command via wpa_supplicant)

root@hw-test:~# wpa_cli
wpa_cli v2.8-devel
Copyright (c) 2004-2019, Jouni Malinen <j@w1.fi> and contributors
...
Selected interface 'mlan0'
Interactive mode

> signal_poll
[  143.963217] mwifiex_sdio mmc2:0001:1: CMD_RESP: cmd 0x23f error, result=0x2
RSSI=-5
LINKSPEED=65
NOISE=-75
FREQUENCY=2437
WIDTH=20 MHz
CENTER_FRQ1=2437
AVG_RSSI=-5

Firmware version is 14.68.35.p66  (latest from linux-firmware git)

The 0x23f command is HostCmd_CMD_STA_CONFIGURE and was added in 4.16 by
    28bf8312a983 ("mwifiex: get_channel from firmware")

I don't see anywhere in the code defining the 0x2 result code.

The error occurs during processing of the netlink
NL80211_CMD_GET_INTERFACE command which is part of
wpa_supplicant's nl80211_signal_poll()

Kernel side callstack is
nl80211_get_interface
    nl80211_send_iface
        mwifiex_cfg80211_get_channel
                mwifiex_get_chan_type
                    mwifiex_get_chan_info
                        mwifiex_send_cmd(HostCmd_CMD_STA_CONFIGURE,
HostCmd_ACT_GEN_GET)


In addition to the log spam the result is also potentially incorrect
since when the command fails a 20MHz channel width is assumed.
The connection still works correctly however

Regards,

Martin