Re: usb full speed isochronous bug ?

On Wed, Oct 10, 2007 at 07:30:35PM -0700, Philip Rakity wrote:
> We have a full speed usb camera attached to an embedded linux solution.
>  the usb core can support full speed devices without a HS hub even
> though it is echi.  (note: using a full speed hub did not solve the
> problem) We found that when we plugged the camera in we could get one
> stream working (video or audio) but not both.
> 
> We saw similar problem with usb sound cards -- we could record or play
> back but NOT both.
> 
> We talked to our IP provider and they gave us a patch (below) that
> works.  We are NOT usb experts so it is possible there are issues with
> the patch but we thought it a good idea to pass it on so.
> 
> We needed to make one addition to the patch.  the goto next is needed !

David, what do you think about the patch below?

thanks,

greg k-h

> --- ehci-sched.c        2007-09-26 11:03:01.000000000 -0700
> +++ /Users/philipr/Desktop/ehci-sched.2.6.22.9.c        2007-10-08
> 22:27:06.000000000 -0700
> @@ -1265,7 +1265,7 @@
>                  */
>                 if (!tt_no_collision (ehci, period_uframes << 3,
>                                 stream->udev, frame, mask))
> -                       return 0;
> +                       goto next;
>  #endif
>  
>                 /* check starts (OUT uses more than one) */
> @@ -2078,6 +2078,7 @@
>  {
>         unsigned        frame, clock, now_uframe, mod;
>         unsigned        modified;
> +               u8      uncompleted_td = 0;
>  
>         mod = ehci->periodic_size << 3;
>  
> @@ -2157,8 +2158,10 @@
>                                         break;
>                                 }
>                                 if (uf != 8)
> +                               {
> +                                       uncompleted_td = 1;
>                                         break;
> -
> +                               }
>                                 /* this one's ready ... HC won't cache
> the
>                                  * pointer for much longer, if at all.
>                                  */
> @@ -2176,6 +2179,7 @@
>                                         hw_p = &q.sitd->hw_next;
>                                         type = Q_NEXT_TYPE
> (q.sitd->hw_next);
>                                         q = *q_p;
> +                                       uncompleted_td = 1;
>                                         break;
>                                 }
>                                 *q_p = q.sitd->sitd_next;
> @@ -2207,12 +2211,15 @@
>  
>                 // FIXME:  likewise assumes HC doesn't halt mid-scan
>  
> +                       if((!uncompleted_td) && (HC_IS_RUNNING
> (ehci_to_hcd(ehci)->state)))
> +                               ehci->next_uframe = now_uframe;
> +
>                 if (now_uframe == clock) {
>                         unsigned        now;
>  
>                         if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
>                                 break;
> -                       ehci->next_uframe = now_uframe;
> +
>                         now = ehci_readl(ehci,
> &ehci->regs->frame_index) % mod;
>                         if (now_uframe == now)
>                                 break;
> 
> 
> 
> 
>        
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