diff options
author | Hans de Goede <hdegoede@redhat.com> | 2012-10-24 18:14:04 +0200 |
---|---|---|
committer | Gerd Hoffmann <kraxel@redhat.com> | 2012-10-25 09:08:09 +0200 |
commit | b4ea86649915eca5551a5166f76e7a9d9032de50 (patch) | |
tree | d5919675b44f6bf14aa8726eab16f0c7c51c205e /hw/usb/hcd-ehci.c | |
parent | e3a36bce1d0123d003855f7731494e6d6f550fcc (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.c | 11 |
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; |