RNDIS Host not working

What would be helpful would be to describe your hardware and cabling configuration in more detail. The BRK board has a micro-USB port that is designed to work as a USB client. There are no other USB ports on the OSD32MP1-BRK board unless you added something to the board (or Octavo has something I am not aware of).

What is not clear either is if you trying to use the OTG role-switching “USB gadget” feature on the BRK board.

You may want to first test OTG host-mode using an OTG cable on another device, for example, HID keyboard or USB flash drive. OTG cable informs the hardware and OS that you want to place the USB in the host role.

Concerning loadable modules, it appears you compiled the module into the kernel and so it may not appear as a loadable module. If you are using OpenSTLinux, verify the module exists:

find /lib/modules/5.10.10/kernel/drivers/usb/gadget -name usb*

Carlos

Take a second look at the device trees for the modified BRK board with the Type-A female USB. Did you generate them using Cube MX? The default device tree from Octavo will probably not work because your “new” hardware differs than a stock BRK board. Check the USB nodes and pinmux assignments in the device tree for the kernel, uboot, and tf-a. The RED board has a USB host and it should serve as an example.

You mentioned that the host USB works with a flash drive or keyboard, but not a USB cable to the peripheral BRK. This suggests that HNP could be failing because both devices are supplying power at the same time and can’t “negotiate” who is the host for OTG. So take a look at the power rails too.

Hi Coloradocarlos,

Thanks for helping us with this issue.

Here is the schematic of the connected hardware:

When we connect a keyboard, USB flash, or a camera instead of the BRK-B board to the USB connector of the BRK-A board, it works, however, it seems that the RNDIS-host driver is not loaded on the BRK-A board, that’s why when we connect the BRK-B to BRK-A, it doesn’t recognize the board.

The schematic is very helpful and a useful visual. This allows us to review chapters 60, 61, and 62 of RM0436.

BRK-A is not bringing up RNDIS because it doesn’t get that far in the initialization. Try “lsusb -v | grep -i gadget” and see if the “Linux Foundation Multifunction Composite Gadget” shows up as one of the devices that are detected. If the Gadget does not come up, then none of the supported “gadgets” like RNDIS will not work. You can also try “lsbusb -t” and see if the rndis_host driver is listed in the classes.

How is BRK-B powered? Is it receiving power from BRK-A USB Type-A or an external source on VIN?

There are two problems here. First, we need to have enumeration on the bus before worrying about RNDIS, but we are not finishing enumeration. (The set a_alt_hnp_support failed: -32 error comes from usb_enumerate_device_otg in drivers/usb/core/hub.c.) Lack of RNDIS host support on BRK A may be a problem, but it is a separate problem to worry about after we make it through enumeration.

Investigating that error, I believe the dwc2 driver may have incorrect HNP/SRP attributes in its OTG descriptor when used as a gadget device in kernel 5.10 (that’s the condensed summary of the mess.)

First, verify that you don’t see BRK B in lsusb from BRK A, even though it is connected. This confirms that the enumeration problem exists.

Now, try disabling OTG on the microUSB connector of BRK B by setting its role to a peripheral. The original 5.10 devicetree from Octavo contains this:

Try changing it as follows and rebuilding the kernel:

This is successful if you no longer see the a_alt_hnp_support error. Unfortunately I’m away from my drawer of Octavo hardware until next semester starts so I can’t test this and it’s very much a shot in the dark. If this does eliminate that error and get BRK B to appear in lsusb, then I will post a full explanation of what was happening and we can proceed to worrying about rndis_host.

If that doesn’t get you anywhere, you could also try adding usb-role-switch; and role-switch-default-mode = "peripheral"; to that same devicetree node.

There are two problems here. First, we need to have enumeration on the bus before worrying about RNDIS, but we are not finishing enumeration. (The a_alt_hnp_support failed: -32 error comes from usb_enumerate_device_otg in drivers/usb/core/hub.c.) Lack of RNDIS host support on BRK A may be a problem, but it is a separate problem to worry about after we make it through enumeration.

Investigating that error, I believe the dwc2 driver may have incorrect HNP/SRP attributes in its OTG descriptor when used as a gadget device in kernel 5.10 (that’s the condensed summary of the mess.)

First, verify that you don’t see BRK B in lsusb from BRK A, even though it is connected. This confirms that the enumeration problem exists.

Now, try disabling OTG on the microUSB connector of BRK B by setting its role to a peripheral. The original 5.10 devicetree from Octavo contains this:

Try changing it as follows and rebuilding the kernel:

This is successful if you no longer see the a_alt_hnp_support error. Unfortunately I’m away from my drawer of Octavo hardware until next semester starts so I can’t test this and it’s very much a shot in the dark. If this does eliminate that error and get BRK B to appear in lsusb, then I will post a full explanation of what was happening and we can proceed to worrying about rndis_host.

If that doesn’t get you anywhere, you could also try adding usb-role-switch; and role-switch-default-mode = "peripheral"; to that same devicetree node.

There are two problems here. First, we need to have enumeration on the bus before worrying about RNDIS, but we are not finishing enumeration. (The a_alt_hnp_support failed: -32 error comes from usb_enumerate_device_otg in drivers/usb/core/hub.c.) Lack of RNDIS host support on BRK A may be a problem, but it is a separate problem to worry about after we make it through enumeration.

Investigating that error, I believe the dwc2 driver may have incorrect HNP/SRP attributes in its OTG descriptor when used as a gadget device in kernel 5.10 (that’s the condensed summary of the mess.)

First, verify that you don’t see BRK B in lsusb from BRK A, even though it is connected. This confirms that the enumeration problem exists.

Now, try disabling OTG on the microUSB connector of BRK B by setting its role to a peripheral. The original 5.10 devicetree from Octavo contains this:

&usbotg_hs{

u-boot,dm-pre-reloc;

status = "okay";

phys = <&usbphyc_port1 0>;

phy-names = "usb2-phy";

};

Try changing it as follows and rebuilding the kernel:

&usbotg_hs{

u-boot,dm-pre-reloc;

status = "okay";

phys = <&usbphyc_port1 0>;

phy-names = "usb2-phy";

dr_mode = "peripheral";

};

The above is successful if you no longer see the a_alt_hnp_support error. Unfortunately I’m away from my drawer of Octavo hardware until next semester starts so I can’t test this and it’s very much a shot in the dark. If this does eliminate that error and get BRK B to appear in lsusb, then I will post a full explanation of what was happening and we can proceed to worrying about rndis_host.

If that doesn’t get you anywhere, you could also try adding usb-role-switch; and role-switch-default-mode = "peripheral"; to that same devicetree node.

• This reply was modified 1 year, 10 months ago by Aedan Cullen.
• This reply was modified 1 year, 10 months ago by Aedan Cullen.

Banjamin,

In order to get an SSH connection over to the peripheral BRK, you will need to know the IP address of that BRK. You can bring up a console on the peripheral BRK by connecting to UART4 via a USB-UART cable, and then look at the output of ifconfig there. If you do not have an IP address, you can assign a static IP on that board and then you will need to use that IP address to SSH into that board from the host BRk board.

Best,

Neeraj