Missing "/sys/class/android_usb/android0/f_rndis/ethaddr"

[Flamefire]

Logcat is showing

E UsbDeviceManager: failed to write to /sys/class/android_usb/android0/f_rndis/ethaddr

And indeed the folder /sys/class/android_usb/android0/f_rndis is missing.

I see chown system system /sys/class/android_usb/android0/f_rndis/ in init.usb.rc so I guess that file is supposed to be there.

Any idea why it is not? Anything missing in the kernel?

[derfelot]

I am guessing it needs to be enabled. You could try either CONFIG_USB_CONFIGFS_QCRNDIS or CONFIG_USB_F_RNDIS . I am guessing the latter

[derfelot]

BTW, those init's are (for the most parts) standard qcom scripts, not all of it needs to be supported by all devices. We tend to go through them to make sure we don't have anything in there that's not needed, but this might have been missed. I also don't have a usb-ethernet adapter I could use to test this.

[Flamefire]

Tried both CONFIG_USB_CONFIGFS_QCRNDIS and CONFIG_USB_CONFIGFS_RNDIS (if I read the Kconfig correctly you are not meant to set CONFIG_USB_F_RNDIS directly) and also noticed that msm-perf_defconfig sets CONFIG_USB_CONFIGFS_QCRNDIS=y

Both attempts fail to compile with a weird kernel/sony/msm8998/drivers/usb/gadget/function/rndis.c:46:1: error: use of undeclared identifier 'KBUILD_MODNAME'
So I guess something in the build scripts is broken.
I found a file out/target/product/lilac/obj/KERNEL_OBJ/drivers/usb/gadget/function/.rndis.o.cmd with

clang [...] -D"KBUILD_STR(s)=$(pound)s" -D"KBUILD_BASENAME=KBUILD_STR(rndis)" -D"KBUILD_MODNAME=KBUILD_STR(usb_f_gsi)" -c -o drivers/usb/gadget/function/.tmp_rndis.o /lineageos/repo/kernel/sony/msm8998/drivers/usb/gadget/function/rndis.c

However I've seen https://patchwork.kernel.org/project/linux-kbuild/patch/1510818396-17443-1-git-send-email-yamada.masahiro@socionext.com/ and indeed the rndis.o file is referenced from usb_f_gsi and usb_f_rndis-y/usb_f_qcrndis-y

But not sure what happened to that patch.

not all of it needs to be supported by all devices

Sure, just warry due to the explicit reference in init.usb.rc

Edit: Looks like this is actually wanted behavior:

 # $(modname_flags) #defines KBUILD_MODNAME as the name of the module it will
 # end up in (or would, if it gets compiled in)
# Note: Files that end up in two or more modules are compiled without the
 #       KBUILD_MODNAME definition. The reason is that any made-up name would
#       differ in different configs.

So we would need to disable CONFIG_USB_F_GSI, but no idea what that is...

Oh and I found whatawurst/android_kernel_sony_msm8998@7c99902

Checking what this RNDIS stuff is I'm not sure if I would want that in the kernel though...