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Re: [Qemu-devel] [PATCH] uhci: improved TD matching, working ISOC transf
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH] uhci: improved TD matching, working ISOC transfers |
Date: |
Fri, 22 Aug 2008 11:23:27 +0200 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Fri, Aug 22, 2008 at 05:54:53AM +0000, Max Krasnyansky wrote:
> While trying to make VX-3000 camera work on XP under KVM I realized that
> we do not necessarily have to find original TD address. All we care about
> is the token which identifies the transfer rather well (direction, endpoint,
> size, etc).
> This is especially important for the isochronous transfers because otherwise
> they are being canceled left and right and we do not make much progress.
>
> With this patch all devices that used bulk transfers that I've tried so
> far continue to work just as well. And now my USB web cammera (isoc transfers)
> is working well tool. It's not as smooth as native Windows but it's pretty
> darn smooth.
>
> The cool thing is that new USB code (both usb-uhci and usb-linux) is totaly
> generic and does not need any special logic for ISOC.
>
> Signed-off-by: Max Krasnyansky <address@hidden>
Thanks, applied.
> ---
> 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 1b15074..0714520 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);
> --
> 1.5.5.1
>
>
>
>
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
`. `' address@hidden | address@hidden
`- people.debian.org/~aurel32 | www.aurel32.net