Android: Two wlan interfaces being active simultaneously

[Joseph P]

I've been able to build latest v5.6.4.2 branch for an Android kernel with Kali Nethunter support.

For reference, here is the diff I applied to build the driver into the kernel:

Common subdirectories: rtl8812au_mod/android and rtl8812au/android
Common subdirectories: rtl8812au_mod/core and rtl8812au/core
Common subdirectories: rtl8812au_mod/docs and rtl8812au/docs
Only in rtl8812au: .git
Only in rtl8812au: .github
Only in rtl8812au: .gitignore
Common subdirectories: rtl8812au_mod/hal and rtl8812au/hal
Common subdirectories: rtl8812au_mod/include and rtl8812au/include
diff rtl8812au_mod/Makefile rtl8812au/Makefile
11,15c11,12
< EXTRA_CFLAGS += -Wno-parentheses-equality
< EXTRA_CFLAGS += -Wno-pointer-bool-conversion
< EXTRA_CFLAGS += -Wno-parentheses-equality
< EXTRA_CFLAGS += -Wno-pointer-bool-conversion
< EXTRA_CFLAGS += -Wno-pragma-pack
---
> #EXTRA_CFLAGS += -Wno-parentheses-equality
> #EXTRA_CFLAGS += -Wno-pointer-bool-conversion
99,100c96,97
< CONFIG_PLATFORM_I386_PC = n
< CONFIG_PLATFORM_ANDROID_ARM64 = y
---
> CONFIG_PLATFORM_I386_PC = y
> CONFIG_PLATFORM_ANDROID_ARM64 = n
1727c1724
< 	$(MAKE) ARCH=$(ARCH) SUBARCH=$(ARCH) REAL_CC=${CC_DIR}/clang CLANG_TRIPLE=aarch64-linux-gnu- CROSS_COMPILE=$(CROSS_COMPILE) -C $(KSRC) M=$(shell pwd) O="$(KBUILD_OUTPUT)" modules
---
> 	$(MAKE) ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) -C $(KSRC) M=$(shell pwd)  modules
Common subdirectories: rtl8812au_mod/os_dep and rtl8812au/os_dep
Common subdirectories: rtl8812au_mod/platform and rtl8812au/platform
Common subdirectories: rtl8812au_mod/tools and rtl8812au/tools

The problem is that when launching Kali Nethunter, there are two wlan interfaces working simultaneously (see fig. below):

• wlan0 (internal wi-fi card);
• wlan1 (? an abstract interface).

wlan1 shows up even if there is no external device plugged in.

I've read about CONFIG_CONCURRENT_MODE that can cause two interfaces working at the same time, but according to Makefile, the -DCONFIG_CONCURRENT_MODE is not passed for CONFIG_PLATFORM_ANDROID_ARM64 option.

So it is currently unclear why there is wlan1 showing up along with wlan0.

[Joseph P]

Alright, I've done some more research on this, and it seems like the driver does not have to do anything with this.
I found in official documentation that this is most likely latest Android's quirk on having multiple interfaces working concurrently.

When my external Wi-Fi adapter is plugged in, the RTL8812AU driver shows up for the wlan2 interface and works properly.

Closing the issue as it no longer serves a purpose.