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authorHans de Goede <hdegoede@redhat.com>2012-10-24 18:14:04 +0200
committerGerd Hoffmann <kraxel@redhat.com>2012-10-25 09:08:09 +0200
commitb4ea86649915eca5551a5166f76e7a9d9032de50 (patch)
treed5919675b44f6bf14aa8726eab16f0c7c51c205e /hw/usb/hcd-ehci.c
parente3a36bce1d0123d003855f7731494e6d6f550fcc (diff)
ehci: Retry to fill the queue while waiting for td completion
If the guest is using multiple transfers to try and keep the usb bus busy / used at maximum efficiency, currently we would see / do the following: 1) submit transfer 1 to the device 2) submit transfer 2 to the device 3) report transfer 1 completion to guest 4) report transfer 2 completion to guest 5) submit transfer 1 to the device 6) report transfer 1 completion to guest 7) submit transfer 2 to the device 8) report transfer 2 completion to guest etc. So after the initial submission we would effectively only have 1 transfer in flight, rather then 2. This is caused by us not checking the queue for addition of new transfers by the guest (ie the resubmission of a recently finished transfer), while waiting for a pending transfer to complete. This patch does add a check for this, changing the sequence to: 1) submit transfer 1 to the device 2) submit transfer 2 to the device 3) report transfer 1 completion to guest 4) submit transfer 1 to the device 5) report transfer 2 completion to guest 6) submit transfer 2 to the device etc. Thus keeping 2 transfers in flight (most of the time, and always 1), as intended by the guest. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'hw/usb/hcd-ehci.c')
-rw-r--r--hw/usb/hcd-ehci.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 8bd87c76d5..a02fe9642f 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -381,7 +381,7 @@ struct EHCIQueue {
uint32_t qhaddr; /* address QH read from */
uint32_t qtdaddr; /* address QTD read from */
USBDevice *dev;
- QTAILQ_HEAD(, EHCIPacket) packets;
+ QTAILQ_HEAD(pkts_head, EHCIPacket) packets;
};
typedef QTAILQ_HEAD(EHCIQueueHead, EHCIQueue) EHCIQueueHead;
@@ -488,6 +488,7 @@ static const char *ehci_mmio_names[] = {
static int ehci_state_executing(EHCIQueue *q);
static int ehci_state_writeback(EHCIQueue *q);
+static int ehci_fill_queue(EHCIPacket *p);
static const char *nr2str(const char **n, size_t len, uint32_t nr)
{
@@ -1994,7 +1995,7 @@ static int ehci_state_fetchqtd(EHCIQueue *q)
{
EHCIqtd qtd;
EHCIPacket *p;
- int again = 0;
+ int again = 1;
get_dwords(q->ehci, NLPTR_GET(q->qtdaddr), (uint32_t *) &qtd,
sizeof(EHCIqtd) >> 2);
@@ -2022,7 +2023,6 @@ static int ehci_state_fetchqtd(EHCIQueue *q)
p = NULL;
}
ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
- again = 1;
} else if (p != NULL) {
switch (p->async) {
case EHCI_ASYNC_NONE:
@@ -2031,6 +2031,9 @@ static int ehci_state_fetchqtd(EHCIQueue *q)
ehci_set_state(q->ehci, q->async, EST_EXECUTE);
break;
case EHCI_ASYNC_INFLIGHT:
+ /* Check if the guest has added new tds to the queue */
+ again = (ehci_fill_queue(QTAILQ_LAST(&q->packets, pkts_head)) ==
+ USB_RET_PROCERR) ? -1 : 1;
/* Unfinished async handled packet, go horizontal */
ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
break;
@@ -2042,13 +2045,11 @@ static int ehci_state_fetchqtd(EHCIQueue *q)
ehci_set_state(q->ehci, q->async, EST_EXECUTING);
break;
}
- again = 1;
} else {
p = ehci_alloc_packet(q);
p->qtdaddr = q->qtdaddr;
p->qtd = qtd;
ehci_set_state(q->ehci, q->async, EST_EXECUTE);
- again = 1;
}
return again;