@@ -2072,7 +2072,7 @@ static int ehci_fill_queue(EHCIPacket *p)
{
EHCIQueue *q = p->queue;
EHCIqtd qtd = p->qtd;
- uint32_t qtdaddr;
+ uint32_t qtdaddr, start_addr = p->qtdaddr;
for (;;) {
if (NLPTR_TBIT(qtd.altnext) == 0) {
@@ -2082,6 +2082,13 @@ static int ehci_fill_queue(EHCIPacket *p)
break;
}
qtdaddr = qtd.next;
+ /*
+ * Detect circular td lists, Windows creates these, counting on the
+ * active bit going low after exection to make the queue stop.
+ */
+ if (qtdaddr == start_addr) {
+ break;
+ }
get_dwords(q->ehci, NLPTR_GET(qtdaddr),
(uint32_t *) &qtd, sizeof(EHCIqtd) >> 2);
ehci_trace_qtd(q, NLPTR_GET(qtdaddr), &qtd);
For ctrl endpoints Windows (atleast Win7) creates circular td lists, so far these were not a problem because we would stop filling the queue if altnext was set. Since further patches in this patchset remove the altnext check this does become a problem and we need detection for going in circles. Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- hw/usb/hcd-ehci.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)