From ade9c6dfbbf573c22800d7ff6df7f0de933e7c96 Mon Sep 17 00:00:00 2001

From: Hans de Goede <hdegoede@redhat.com>

Date: Wed, 12 Sep 2012 15:08:32 +0200

Subject: [PATCH] ehci: Don't set seen to 0 when removing unseen queue-heads

When removing unseen queue-heads from the async queue list, we should not

set the seen flag to 0, as this may cause them to be removed by

ehci_queues_rip_unused() during the next call to ehci_advance_async_state()

if the timer is late or running at a low frequency.

Note:

1) This *may* have caused the instant unlink / relinks described in commit

   9bc3a3a216e2689bfcdd36c3e079333bbdbf3ba0

2) Rather then putting more if-s inside ehci_queues_rip_unused, this patch

   instead introduces a new ehci_queues_rip_unseen function.

3) This patch also makes it save to call ehci_queues_rip_unseen() multiple

   times, which gets used in the folluw up patch titled:

   "ehci: Walk async schedule before and after migration"

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

(cherry picked from commit 8f5457eb04140714eaf57a99bc08dc661d83fa87)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

---

 hw/usb/hcd-ehci.c | 24 ++++++++++++++++++------

 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c

index 017a01d..bc86460 100644

--- a/hw/usb/hcd-ehci.c

+++ b/hw/usb/hcd-ehci.c

@@ -848,10 +848,10 @@ static EHCIQueue *ehci_find_queue_by_qh(EHCIState *ehci, uint32_t addr,

     return NULL;

 }

-static void ehci_queues_rip_unused(EHCIState *ehci, int async, int flush)

+static void ehci_queues_rip_unused(EHCIState *ehci, int async)

 {

     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;

-    const char *warn = (async && !flush) ? "guest unlinked busy QH" : NULL;

+    const char *warn = async ? "guest unlinked busy QH" : NULL;

     uint64_t maxage = FRAME_TIMER_NS * ehci->maxframes * 4;

     EHCIQueue *q, *tmp;

@@ -861,13 +861,25 @@ static void ehci_queues_rip_unused(EHCIState *ehci, int async, int flush)

             q->ts = ehci->last_run_ns;

             continue;

         }

-        if (!flush && ehci->last_run_ns < q->ts + maxage) {

+        if (ehci->last_run_ns < q->ts + maxage) {

             continue;

         }

         ehci_free_queue(q, warn);

     }

 }

+static void ehci_queues_rip_unseen(EHCIState *ehci, int async)

+{

+    EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;

+    EHCIQueue *q, *tmp;

+

+    QTAILQ_FOREACH_SAFE(q, head, next, tmp) {

+        if (!q->seen) {

+            ehci_free_queue(q, NULL);

+        }

+    }

+}

+

 static void ehci_queues_rip_device(EHCIState *ehci, USBDevice *dev, int async)

 {

     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;

@@ -1700,7 +1712,7 @@ static int ehci_state_waitlisthead(EHCIState *ehci,  int async)

         ehci_set_usbsts(ehci, USBSTS_REC);

     }

-    ehci_queues_rip_unused(ehci, async, 0);

+    ehci_queues_rip_unused(ehci, async);

     /*  Find the head of the list (4.9.1.1) */

     for(i = 0; i < MAX_QH; i++) {

@@ -2332,7 +2344,7 @@ static void ehci_advance_async_state(EHCIState *ehci)

          */

         if (ehci->usbcmd & USBCMD_IAAD) {

             /* Remove all unseen qhs from the async qhs queue */

-            ehci_queues_rip_unused(ehci, async, 1);

+            ehci_queues_rip_unseen(ehci, async);

             trace_usb_ehci_doorbell_ack();

             ehci->usbcmd &= ~USBCMD_IAAD;

             ehci_raise_irq(ehci, USBSTS_IAA);

@@ -2385,7 +2397,7 @@ static void ehci_advance_periodic_state(EHCIState *ehci)

         ehci_set_fetch_addr(ehci, async,entry);

         ehci_set_state(ehci, async, EST_FETCHENTRY);

         ehci_advance_state(ehci, async);

-        ehci_queues_rip_unused(ehci, async, 0);

+        ehci_queues_rip_unused(ehci, async);

         break;

     default: