[Qemu-devel] [PATCH 03/10] ehci: Better detection for qtd-s linked in circles

[Hans de Goede <hdegoede@redhat.com>]

Windows links interrupt qtd-s in circles, which means that when interrupt
endpoints return USB_RET_ASYNC, combined with the recent
"ehci: Retry to fill the queue while waiting for td completion" patch,
we keep adding the tds to the queue over and over again, as we detect the
circle from fill_queue, but we call it over and over again ...

This patch fixes this by changing the circle detection to also detect
circling into tds already queued up previously.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 hw/usb/hcd-ehci.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 5e3b4a8..89b7520 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -1790,7 +1790,7 @@ static int ehci_fill_queue(EHCIPacket *p)
     USBEndpoint *ep = p->packet.ep;
     EHCIQueue *q = p->queue;
     EHCIqtd qtd = p->qtd;
-    uint32_t qtdaddr, start_addr = p->qtdaddr;
+    uint32_t qtdaddr;
 
     for (;;) {
         if (NLPTR_TBIT(qtd.next) != 0) {
@@ -1801,8 +1801,10 @@ static int ehci_fill_queue(EHCIPacket *p)
          * Detect circular td lists, Windows creates these, counting on the
          * active bit going low after execution to make the queue stop.
          */
-        if (qtdaddr == start_addr) {
-            break;
+        QTAILQ_FOREACH(p, &q->packets, next) {
+            if (p->qtdaddr == qtdaddr) {
+                goto leave;
+            }
         }
         get_dwords(q->ehci, NLPTR_GET(qtdaddr),
                    (uint32_t *) &qtd, sizeof(EHCIqtd) >> 2);
@@ -1819,6 +1821,7 @@ static int ehci_fill_queue(EHCIPacket *p)
         assert(p->packet.status == USB_RET_ASYNC);
         p->async = EHCI_ASYNC_INFLIGHT;
     }
+leave:
     usb_device_flush_ep_queue(ep->dev, ep);
     return 1;
 }
-- 
1.7.12.1