[Qemu-devel] [PATCH] usb-linux: allow multiple devices with matching IDs

[Grazvydas Ignotas <notasas@gmail.com>]

Right now if we pass through multiple USB devices with matching vendor
and product IDs, only first one is passed to guest, as the code thinks
second device is already attached. The only way to get those devices
working is to specify bus.addr which is inconvenient if devices are
frequently replugged on host, because the address changes after replug.

Fix this by checking bus.addr before assuming the device is already
attached. This way -usbdevice host:1234:1234 -usbdevice host:1234:1234
will pass through 2 devices correctly.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
---
 usb-linux.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/usb-linux.c b/usb-linux.c
index c3c38ec..b5f1396 100644
--- a/usb-linux.c
+++ b/usb-linux.c
@@ -1464,9 +1464,13 @@ static int usb_host_auto_scan(void *opaque, int bus_num, int addr,
         }
         /* We got a match */
 
-        /* Already attached ? */
         if (s->fd != -1) {
-            return 0;
+            /* Already attached? */
+            if (s->bus_num == bus_num && s->addr == addr)
+                return 0;
+
+            /* Not attached but needs another hostdev */
+            continue;
         }
         DPRINTF("husb: auto open: bus_num %d addr %d\n", bus_num, addr);
 
-- 
1.6.3.3