diff options
| author | John Stultz <john.stultz@linaro.org> | 2011-09-14 12:07:50 -0700 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2011-09-14 12:07:50 -0700 |
| commit | 8e5922b81be9a9548c0cee8ffe3d14bb58b95387 (patch) | |
| tree | 72356bc5d1fe562cb62f9c4d9e0d8fcd44f8b775 /drivers/usb/host/ehci-q.c | |
| parent | 3f1fc539a29e09d940df1418b36d23621f85d545 (diff) | |
| parent | f392cbf75615e9d8cb90ef5ffb8d4e752b7be3c7 (diff) | |
Merge branch 'upstream/linaro-3.0' into linaro-android-3.0
Conflicts:
arch/arm/kernel/entry-armv.S
Diffstat (limited to 'drivers/usb/host/ehci-q.c')
| -rw-r--r-- | drivers/usb/host/ehci-q.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index 0917e3a3246..b7f9496e4f0 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -995,6 +995,12 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh) head->qh_next.qh = qh; head->hw->hw_next = dma; + /* + * flush qh descriptor into memory immediately, + * see comments in qh_append_tds. + */ + ehci_sync_mem(); + qh_get(qh); qh->xacterrs = 0; qh->qh_state = QH_STATE_LINKED; @@ -1082,6 +1088,18 @@ static struct ehci_qh *qh_append_tds ( wmb (); dummy->hw_token = token; + /* + * Writing to dma coherent buffer on ARM may + * be delayed to reach memory, so HC may not see + * hw_token of dummy qtd in time, which can cause + * the qtd transaction to be executed very late, + * and degrade performance a lot. ehci_sync_mem + * is added to flush 'token' immediatelly into + * memory, so that ehci can execute the transaction + * ASAP. + */ + ehci_sync_mem(); + urb->hcpriv = qh_get (qh); } } |