Not all USB devices have interfaces. This is true in particular of the STMicroelectronics STEVAL-USBC2DP Type-C to DisplayPort adapter, as well as possibly other USB-C devices. As a result these devices do not show up in the output from "lsusb -t", because the logic in print_tree_dev_interface() lists interfaces, not devices (as implied by the function's name). This means that the output from "lsusb -t" can be inconsistent with the output from "lsusb", since some devices are omitted. To fix the problem, we make the subroutine call print_usbdevice() at least once even if the device has no interfaces, and make the latter routine print a minimal description of such devices (anything that does not require access to the interface descriptor). Reported-and-tested-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx> Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/linux-usb/70c563f1-847c-32a1-cf4d-6bf9802017ab@xxxxxxxxxxxx/ --- lsusb-t.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) Index: usbutils-master/lsusb-t.c =================================================================== --- usbutils-master.orig/lsusb-t.c +++ usbutils-master/lsusb-t.c @@ -183,9 +183,12 @@ static void print_usbdevice(struct usbde char lanes[32]; lanes_to_str(lanes, d->tx_lanes, d->rx_lanes); - get_class_string(subcls, sizeof(subcls), i->bInterfaceClass); + if (i) + get_class_string(subcls, sizeof(subcls), i->bInterfaceClass); - if (i->bInterfaceClass == 9) + if (!i) + printf("Port %03u: Dev %03u, %sM%s\n", d->portnum, d->devnum, d->speed, lanes); + else if (i->bInterfaceClass == 9) printf("Port %03u: Dev %03u, If %u, Class=%s, Driver=%s/%up, %sM%s\n", d->portnum, d->devnum, i->ifnum, subcls, i->driver, d->maxchild, d->speed, lanes); else @@ -690,11 +693,12 @@ static void sort_busses(void) static void print_tree_dev_interface(struct usbdevice *d, struct usbinterface *i) { indent += 3; - while (i) { + do { printf(" %*s", indent, "|__ "); print_usbdevice(d, i); - i = i->next; - } + if (i) + i = i->next; + } while (i); indent -= 3; } static void print_tree_dev_children(struct usbdevice *d)
