[Qemu-devel] [PATCH v2] usb-host: support devices with sparse/non-sequential USB interfaces

[Samuel Brian <sam.brian@accelerated.com>]

Some USB devices have sparse interface numbering which is not able to be
passthroughed.
For example, the Sierra Wireless MC7455/MC7430:

  # lsusb  -D /dev/bus/usb/003/003 | egrep '1199|9071|bNumInterfaces|bInterfaceNumber'
  Device: ID 1199:9071 Sierra Wireless, Inc.
    idVendor           0x1199 Sierra Wireless, Inc.
    idProduct          0x9071
      bNumInterfaces          5
        bInterfaceNumber        0
        bInterfaceNumber        2
        bInterfaceNumber        3
        bInterfaceNumber        8
        bInterfaceNumber       10

In this case, the interface numbers are 0, 2, 3, 8, 10 and not the
0, 1, 2, 3, 4 that QEMU tries to claim.

This change allows sparse USB interface numbering.
Instead of only claiming the interfaces in the range reported by the USB
device through bNumInterfaces, QEMU attempts to claim all possible
interfaces.

v2 to fix broken v1 patch formatting.

Signed-off-by: Samuel Brian <sam.brian@accelerated.com>
---
 hw/usb/host-libusb.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
index f9c8eafe06..2e3a752ef6 100644
--- a/hw/usb/host-libusb.c
+++ b/hw/usb/host-libusb.c
@@ -1107,7 +1107,7 @@ static void usb_host_detach_kernel(USBHostDevice *s)
     if (rc != 0) {
         return;
     }
-    for (i = 0; i < conf->bNumInterfaces; i++) {
+    for (i = 0; i < USB_MAX_INTERFACES; i++) {
         rc = libusb_kernel_driver_active(s->dh, i);
         usb_host_libusb_error("libusb_kernel_driver_active", rc);
         if (rc != 1) {
@@ -1130,7 +1130,7 @@ static void usb_host_attach_kernel(USBHostDevice *s)
     if (rc != 0) {
         return;
     }
-    for (i = 0; i < conf->bNumInterfaces; i++) {
+    for (i = 0; i < USB_MAX_INTERFACES; i++) {
         if (!s->ifs[i].detached) {
             continue;
         }
@@ -1145,7 +1145,7 @@ static int usb_host_claim_interfaces(USBHostDevice *s, int configuration)
 {
     USBDevice *udev = USB_DEVICE(s);
     struct libusb_config_descriptor *conf;
-    int rc, i;
+    int rc, i, claimed;
 
     for (i = 0; i < USB_MAX_INTERFACES; i++) {
         udev->altsetting[i] = 0;
@@ -1164,14 +1164,19 @@ static int usb_host_claim_interfaces(USBHostDevice *s, int configuration)
         return USB_RET_STALL;
     }
 
-    for (i = 0; i < conf->bNumInterfaces; i++) {
+    claimed = 0;
+    for (i = 0; i < USB_MAX_INTERFACES; i++) {
         trace_usb_host_claim_interface(s->bus_num, s->addr, configuration, i);
         rc = libusb_claim_interface(s->dh, i);
-        usb_host_libusb_error("libusb_claim_interface", rc);
-        if (rc != 0) {
-            return USB_RET_STALL;
+        if (rc == 0) {
+             s->ifs[i].claimed = true;
+             if (++claimed == conf->bNumInterfaces) {
+                break;
+             }
         }
-        s->ifs[i].claimed = true;
+    }
+    if (claimed != conf->bNumInterfaces) {
+        return USB_RET_STALL;
     }
 
     udev->ninterfaces   = conf->bNumInterfaces;
@@ -1183,10 +1188,9 @@ static int usb_host_claim_interfaces(USBHostDevice *s, int configuration)
 
 static void usb_host_release_interfaces(USBHostDevice *s)
 {
-    USBDevice *udev = USB_DEVICE(s);
     int i, rc;
 
-    for (i = 0; i < udev->ninterfaces; i++) {
+    for (i = 0; i < USB_MAX_INTERFACES; i++) {
         if (!s->ifs[i].claimed) {
             continue;
         }
-- 
2.11.0