On Wed, 22 Mar 2000, Gregory P. Smith wrote:
> Would it make sense to hypothesize [without looking at the code] that
> Roman's driver may be forgetting a virt_to_bus call somewhere when filling
> in an address for an ED or TD?  Some controllers may magically not barf

[DISCLAIMER] I'd call myself beginner with regards to USB and
OHCI. Ok, I glanced through the OHCI documents just now. :)

I tried to search for all the accesses to (td|ed)->hw[a-zA-Z]+ and
couldn't find a missing virt_to_bus or bus_to_virt for that matter.

However even if this is a non-issue I'd like to get an explanation to
this. sohci_submit_urb calls td_submit_urb:

        td_submit_urb (urb);

which if I understood signals that HC is free to do its stuff by writing
appropriate bits in the cmdStatus register. Then however there is this
code

        if (ed->state != ED_OPER) 
                ep_link (ohci, ed);

seems to mess with the eds and tds which I thought was a big no-no when HC
is working?

I am at work so can't test this but how about if we switch these two
statements: 

--- usb-ohci.c.bak      Thu Mar 23 11:33:15 2000
+++ usb-ohci.c  Thu Mar 23 11:33:31 2000
@@ -329,11 +329,11 @@
                urb->start_frame = ((ed->state == ED_OPER)? (ed->last_iso + 1):
                                                                (le16_to_cpu 
(ohci->hcca.frame_no) + 10)) & 0xffff;
        }
-
-       td_submit_urb (urb); /* fill the TDs and link it to the ed */

        if (ed->state != ED_OPER)  /* link the ed into a chain if is not already */
                ep_link (ohci, ed);
+
+       td_submit_urb (urb); /* fill the TDs and link it to the ed */
        spin_unlock_irqrestore (&usb_ed_lock, flags);

        urb->status = USB_ST_URB_PENDING; 


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