u3g and ubsa
Vladimir Grebenschikov
vova at fbsd.ru
Wed Nov 26 02:46:23 PST 2008
On Wed, 2008-11-26 at 10:29 +0100, Nick Hibma wrote:
> Could you try the following:
>
> Change the ibufsize and obufsize values to a power of 2 in u3g_attach:
>
> ucom->sc_ibufsize = 4096;
> ucom->sc_ibufsizepad = ucom->sc_ibufsize;
> ucom->sc_obufsize = 4096;
>
> Perhaps the USB stack does not like arbitrarily sized buffers due to
> transfer rollovers at the end of the buffer / memory page or something.
>
> If that does not work could you lower it to 512, and if that does not work
> change it to:
>
> ucom->sc_ibufsize = UGETW(ed->wMaxPacketSize);
> ucom->sc_ibufsizepad = ucom->sc_ibufsize;
> ucom->sc_obufsize = UGETW(ed->wMaxPacketSize);
>
> That last case is worst case as it would considerably increase overhead,
> especially in USB 1.0 cases where the max. wMaxPacketSize is 64 bytes.
All cases makes same panic on connecting to port:
ohci.c:545 ohci_alloc_std_chain: XXX need to copy
> If it works I'd be interested to hear about performance (download from SUN
> is always a good one), and any messages in dmesg or in a ppp logfile for
> dropped chars, and invalid FCS.
>
> Cheers,
>
> Nick
--
Vladimir B. Grebenschikov
vova at fbsd.ru
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