RE: AP mode on RTW88 8821cs

[Ping-Ke Shih <pkshih@realtek.com>]

> -----Original Message-----
> From: Konstantin Kletschke <konstantin.kletschke@inside-m2m.de>
> Sent: Thursday, March 21, 2024 6:56 PM
> To: linux-wireless@vger.kernel.org
> Subject: AP mode on RTW88 8821cs
> 
> We have a rockchip rk3328 board with an 8821cs chip connected via SDIO.
> Well, cs impiles SDIO, cu is USB variant.
> 
> Normally thinks work quite well for use but we do not get AP mode to
> work.
> We use 6.5.13 kernel with our customized DT and the in kernel 8821cs
> driver:
> 
> rtw88_8821cs           12288  0
> onboard_usb_hub        12288  0
> rtw88_8821c            81920  1 rtw88_8821cs
> crct10dif_ce           12288  1
> rtw88_sdio             24576  1 rtw88_8821cs
> rtw88_core            167936  2 rtw88_8821c,rtw88_sdio
> mac80211              929792  2 rtw88_sdio,rtw88_core
> libarc4                12288  1 mac80211
> cfg80211              921600  2 rtw88_core,mac80211
> 
> We tried with wpa_cli and hostapd but to no avail.
> I tried hostapd with wlan0 and eth0 bridged into br0, the SSID appears
> in the wlan search results in other devices, connectig _seems_ to work
> but getting an IP is not possible.
> 
> What my colleauge and me especially noticed, the TX counter for the
> wlan0 interface in this use case runs, RX stays at 0:
> 
> br0       Link encap:Ethernet  HWaddr 4A:86:7D:63:5C:59
>           inet addr:10.16.10.103  Bcast:10.16.255.255  Mask:255.255.0.0
>           inet6 addr: fe80::4886:7dff:fe63:5c59/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:111361 errors:0 dropped:3479 overruns:0 frame:0
>           TX packets:28144 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:13333769 (12.7 MiB)  TX bytes:3847859 (3.6 MiB)
> 
> eth0      Link encap:Ethernet  HWaddr 86:E0:C0:EA:FA:A8
>           inet6 addr: fe80::84e0:c0ff:feea:faa8/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:112803 errors:0 dropped:219 overruns:0 frame:0
>           TX packets:28405 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:15102222 (14.4 MiB)  TX bytes:3891727 (3.7 MiB)
>           Interrupt:51
> 
> wlan0     Link encap:Ethernet  HWaddr F0:B0:40:4F:70:BC
>           inet6 addr: fe80::f2b0:40ff:fe4f:70bc/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:123446 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:0 (0.0 B)  TX bytes:18783966 (17.9 MiB)
> 
> In order to provide useful debug information, what should I look into?
> 
> Is it a known issue or should AP mode work flawlessly with those
> drivers, which implies I forgot something.
> When I use my software with an external USB WLAN stick with another
> driver, exchange all wlan0 by wlan1 occurences only:
> 
> rtl8xxxu              192512  0
> rtl8192cu              81920  0
> rtl_usb                16384  1 rtl8192cu
> rtl8192c_common        65536  1 rtl8192cu
> rtlwifi               118784  3 rtl8192c_common,rtl_usb,rtl8192cu
> 
> the software AP works immediately.
> 

We had similar discussion before [1]. I think Martin will take his time to
investigate how to enable AP mode on SDIO WiFi cards.

[1] https://lore.kernel.org/linux-wireless/36972ff5-0c48-4bd2-8f9a-9649bfa24225@lexina.in/