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Re: [Qemu-devel] "usb: uhci: Look up queue by address, not token"
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] "usb: uhci: Look up queue by address, not token" |
Date: |
Fri, 16 Nov 2012 11:25:27 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0.10) Gecko/20121026 Thunderbird/10.0.10 |
On 11/15/12 16:40, Jan Kiszka wrote:
> Hi Hans,
>
> On 2012-11-15 16:19, Hans de Goede wrote:
>> Hi Jan,
>>
>> I just saw your $subject patch in Gerd's usb-next tree, and I've a question
>> about it. The token should be enough to uniquely identify a device + ep,
>> and unless a guest uses multiple qhs for a singe ep, that _should_ be enough.
>
> But what disallows that the guest issues multiple requests (QH + series
> of TDs) for a single endpoint? I'm not finding any trace in the spec
> that disallows this. And my special guest is stumbling over that
> limitation in QEMU.
The order which the TDs from the two QHs are filled is undefined I
think, so why a guest would do that?
I guess I'll push back the patch in the queue and don't include it into
the 1.3 pull req until this is sorted.
cheers,
Gerd