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authorHans de Goede <hdegoede@redhat.com>2012-08-17 15:24:49 +0200
committerGerd Hoffmann <kraxel@redhat.com>2012-08-31 11:55:17 +0200
commit0132b4b6595423c92f54d7e0b172b5d73aaa8375 (patch)
treefe8b47682db22a2829fccd10f9b408689beaeb39 /hw/usb/core.c
parentda9fbe76a0639c529f9678aabcc052dfe4cd9cc4 (diff)
usb: Halt ep queue en cancel pending packets on a packet error
For controllers which queue up more then 1 packet at a time, we must halt the ep queue, and inside the controller code cancel all pending packets on an error. There are multiple reasons for this: 1) Guests expect the controllers to halt ep queues on error, so that they get the opportunity to cancel transfers which the scheduled after the failing one, before processing continues 2) Not cancelling queued up packets after a failed transfer also messes up the controller state machine, in the case of EHCI causing the following assert to trigger: "assert(p->qtdaddr == q->qtdaddr)" at hcd-ehci.c:2075 3) For bulk endpoints with pipelining enabled (redirection to a real USB device), we must cancel all the transfers after this a failed one so that: a) If they've completed already, they are not processed further causing more stalls to be reported, originating from the same failed transfer b) If still in flight, they are cancelled before the guest does a clear stall, otherwise the guest and device can loose sync! Note this patch only touches the ehci and uhci controller changes, since AFAIK no other controllers actually queue up multiple transfer. If I'm wrong on this other controllers need to be updated too! Also note that this patch was heavily tested with the ehci code, where I had a reproducer for a device causing a transfer to fail. The uhci code is not tested with actually failing transfers and could do with a thorough review! Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'hw/usb/core.c')
-rw-r--r--hw/usb/core.c35
1 files changed, 28 insertions, 7 deletions
diff --git a/hw/usb/core.c b/hw/usb/core.c
index c7e5bc047f..28b840e52d 100644
--- a/hw/usb/core.c
+++ b/hw/usb/core.c
@@ -382,12 +382,23 @@ int usb_handle_packet(USBDevice *dev, USBPacket *p)
usb_packet_check_state(p, USB_PACKET_SETUP);
assert(p->ep != NULL);
+ /* Submitting a new packet clears halt */
+ if (p->ep->halted) {
+ assert(QTAILQ_EMPTY(&p->ep->queue));
+ p->ep->halted = false;
+ }
+
if (QTAILQ_EMPTY(&p->ep->queue) || p->ep->pipeline) {
ret = usb_process_one(p);
if (ret == USB_RET_ASYNC) {
usb_packet_set_state(p, USB_PACKET_ASYNC);
QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
} else {
+ /*
+ * When pipelining is enabled usb-devices must always return async,
+ * otherwise packets can complete out of order!
+ */
+ assert(!p->ep->pipeline);
p->result = ret;
usb_packet_set_state(p, USB_PACKET_COMPLETE);
}
@@ -399,6 +410,20 @@ int usb_handle_packet(USBDevice *dev, USBPacket *p)
return ret;
}
+static void __usb_packet_complete(USBDevice *dev, USBPacket *p)
+{
+ USBEndpoint *ep = p->ep;
+
+ assert(p->result != USB_RET_ASYNC && p->result != USB_RET_NAK);
+
+ if (p->result < 0) {
+ ep->halted = true;
+ }
+ usb_packet_set_state(p, USB_PACKET_COMPLETE);
+ QTAILQ_REMOVE(&ep->queue, p, queue);
+ dev->port->ops->complete(dev->port, p);
+}
+
/* Notify the controller that an async packet is complete. This should only
be called for packets previously deferred by returning USB_RET_ASYNC from
handle_packet. */
@@ -409,11 +434,9 @@ void usb_packet_complete(USBDevice *dev, USBPacket *p)
usb_packet_check_state(p, USB_PACKET_ASYNC);
assert(QTAILQ_FIRST(&ep->queue) == p);
- usb_packet_set_state(p, USB_PACKET_COMPLETE);
- QTAILQ_REMOVE(&ep->queue, p, queue);
- dev->port->ops->complete(dev->port, p);
+ __usb_packet_complete(dev, p);
- while (!QTAILQ_EMPTY(&ep->queue)) {
+ while (!ep->halted && !QTAILQ_EMPTY(&ep->queue)) {
p = QTAILQ_FIRST(&ep->queue);
if (p->state == USB_PACKET_ASYNC) {
break;
@@ -425,9 +448,7 @@ void usb_packet_complete(USBDevice *dev, USBPacket *p)
break;
}
p->result = ret;
- usb_packet_set_state(p, USB_PACKET_COMPLETE);
- QTAILQ_REMOVE(&ep->queue, p, queue);
- dev->port->ops->complete(dev->port, p);
+ __usb_packet_complete(ep->dev, p);
}
}