I'm running the usb_host_lib example and I have a hub connected with an FTDI device attached to the hub. The usb_host_lib program lists the hub but does not see the FTDI device attached to it. However, I also get this error message:
The USB Host Stack currently only supports a single device (i.e., full hub support has not been added yet). See the
host stack docs for more information. Currently, the Host stack should be able to see your connected Hub (since it's a device), but it won't detect/talk to any devices further down stream.
However, I also get this error message:
HUB: Bad transfer status: CHECK_SHORT_LANGID_TABLE
This is a non-fatal error printed by the hub driver. It means that during enumeration, the hub driver tried to fetch the connected device's language ID table descriptor in order to see what languages are supported by the device. However, some non-compliant devices will sometimes return all 0's or when requested for the LANG ID table.
In this case, the hub driver will continue on with enumeration but skip all further enumeration stages relating to string descriptors. The hub driver basically just treats the device as if the device did not support any string descriptors.
You can increase the ESP LOG level in menuconfig to also print WARNING logs. The Hub driver will dump more logging information.