Re: [Qemu-devel] Preliminary patch to implement ehci

[Mark Burkley]

On Fri, 31 Oct 2008 13:54:45 -0700, you wrote:

>Anthony Liguori wrote:
>> Mark Burkley wrote:
>>> Hi Anthony,
>>>
>>> I have ehci built against trunk now but I am seeing an issue with a
>>> memory key I am using for testing.  ioctl returns EPIPE (which I
>>> would have thought was a STALL) to an asynchronous IN completion in
>>> usb-linux.c but then this is returned as USB_RET_NAK to EHCI which
>>> confuses my WinXP target because the transfer is then never
>>> completed.
>>> 
>>> Can I just check that it was intentional to return NAK for EPIPE 
>>> returns in asynchronous completions?  If so, then I will try to
>>> detect the stall in my implementation and treat differently to a
>>> NAK.  It's just that if I modify usb-linux.c to return
>>> USB_RET_STALL on -EPIPE then it works fine.
>
>I just looked at the usb-linuc.c:async_complete() code and it looks like 
>it was intentional but I cannot remember why I wrote that way. And what 
>you're saying makes sense. ie It should be a STALL. In fact I think that 
>might fix the regression with USB storage devices that some people have 
>reported.
>I'll play some more with this later today. I want to make sure that the 
>change we're talking about does not break existing devices that I 
>thoroughly tested as part of the usb async re-write. If everything works 
>as expected then we'll change it.
>
>btw It's awesome that you're working on EHCI. I was going to work on it 
>right after making the stack fully async but got swamped with other 
>things. Do you have a git tree I could pull your stuff from ?

Thanks for that - happy to be a contributor.  I don't have git
installed but I did post a patch against svn trunk 5571 yesterday if
that helps.  I'll have a look and see what's involved in setting up
git as well.

>Thanx
>Max
>