diff options
| -rw-r--r-- | hw/usb-uhci.c | 40 |
1 files changed, 28 insertions, 12 deletions
diff --git a/hw/usb-uhci.c b/hw/usb-uhci.c index 3231a3ec20..62c743d583 100644 --- a/hw/usb-uhci.c +++ b/hw/usb-uhci.c @@ -265,25 +265,41 @@ static void uhci_async_cancel_all(UHCIState *s) static UHCIAsync *uhci_async_find_td(UHCIState *s, uint32_t addr, uint32_t token) { UHCIAsync *async = s->async_pending; + UHCIAsync *match = NULL; + int count = 0; + + /* + * We're looking for the best match here. ie both td addr and token. + * Otherwise we return last good match. ie just token. + * It's ok to match just token because it identifies the transaction + * rather well, token includes: device addr, endpoint, size, etc. + * + * Also since we queue async transactions in reverse order by returning + * last good match we restores the order. + * + * It's expected that we wont have a ton of outstanding transactions. + * If we ever do we'd want to optimize this algorithm. + */ while (async) { - if (async->td == addr) { - if (async->token == token) - return async; - - /* - * TD was reused for a different transfer. - * Invalidate the original one asap. - */ - if (async->valid > 0) { - async->valid = 0; - dprintf("husb: bad reuse. td 0x%x\n", async->td); + if (async->token == token) { + /* Good match */ + match = async; + + if (async->td == addr) { + /* Best match */ + break; } } async = async->next; + count++; } - return NULL; + + if (count > 64) + fprintf(stderr, "uhci: warning lots of async transactions\n"); + + return match; } static void uhci_attach(USBPort *port1, USBDevice *dev); |