From: Junjie Cao <[email protected]>
usb_host_auto_check() gives up on a matching device once three opens
have failed, and clears the failure count only when a scan finds no
matching device at all. A device that re-enumerates, e.g. after a
firmware reboot, is closed on NO_DEVICE and usb_host_close() rescans at
once, while libusb still lists the old address: that open fails and
counts, the next 2 s scan opens the new address, and nothing clears the
count. After the third such cycle the device is skipped until a scan
finds it absent or the usb-host device is re-added.
Clear the count once an open succeeds. A device that cannot be opened at
all still stops after three attempts.
The source-level fixture attached to #4673 reproduces the same sequence;
its remaining cases expect a failure budget per enumerated device, which
this change does not add.
Fixes: 3ee886c5ba77 ("usb-host: limit open retries")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/4631
Buglink: https://gitlab.com/qemu-project/qemu/-/issues/4673
Cc: [email protected]
Reported-by: Farid <[email protected]>
Reported-by: Prateek Rungta <https://gitlab.com/prateek2>
Suggested-by: Farid <[email protected]>
Signed-off-by: Junjie Cao <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Thomas Huth <[email protected]>
---
hw/usb/host-libusb.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
index 8f7ced95cfe..5a369e2ebf5 100644
--- a/hw/usb/host-libusb.c
+++ b/hw/usb/host-libusb.c
@@ -1924,6 +1924,7 @@ static void usb_host_auto_check(void *unused)
s->errcount++;
continue;
}
+ s->errcount = 0;
break;
}
}
--
2.56.0
