[PATCH] ohci, control/enumeration fix

One of the flakey things I see with 2.5.29 is that many
devices give trouble enumerating.  uhci still oopses khubd
enumerating pegasus (many control message errors first).
But that's not the only troublesome combo.

This patch fixes a failure that would hang the ohci driver
It's basically avoiding a few less IRQs (most noticable
with ISO), in this case so that a wedged SET_ADDRESS completes.
(Instead of hanging khubd in 'D' state.)  And it also updates
a diagnostic to provide more troubleshooting help for similar
issues in the future.

drivers/usb/host/ohci-q.c

@@ -534,6 +534,8 @@ td_fill (unsigned int info,
 	/* aim for only one interrupt per urb.  mostly applies to control
 	 * and iso; other urbs rarely need more than one TD per urb.
 	 * this way, only final tds (or ones with an error) cause IRQs.
+	 * at least immediately; use DI=6 in case any control request is
+	 * tempted to die part way through.
 	 *
 	 * NOTE: could delay interrupts even for the last TD, and get fewer
 	 * interrupts ... increasing per-urb latency by sharing interrupts.
@@ -541,7 +543,7 @@ td_fill (unsigned int info,
 	 */
 	if (index != (urb_priv->length - 1)
 			|| (urb->transfer_flags & URB_NO_INTERRUPT))
-		info |= TD_DI_SET (7);
+		info |= TD_DI_SET (6);
 
 	/* use this td as the next dummy */
 	td_pt = urb_priv->td [index];
@@ -809,12 +811,16 @@ static struct td *dl_reverse_done_list (struct ohci_hcd *ohci)
 	ohci->hcca->done_head = 0;
 
 	while (td_list_hc) {		
+	    	int		cc;
+
 		td_list = dma_to_td (ohci, td_list_hc);
 
 		td_list->hwINFO |= cpu_to_le32 (TD_DONE);
 
-		if (TD_CC_GET (le32_to_cpup (&td_list->hwINFO))) {
+		cc = TD_CC_GET (le32_to_cpup (&td_list->hwINFO));
+		if (cc != TD_CC_NOERROR) {
 			urb_priv = (urb_priv_t *) td_list->urb->hcpriv;
+
 			/* Non-iso endpoints can halt on error; un-halt,
 			 * and dequeue any other TDs from this urb.
 			 * No other TD could have caused the halt.
@@ -822,12 +828,21 @@ static struct td *dl_reverse_done_list (struct ohci_hcd *ohci)
 			if (td_list->ed->hwHeadP & ED_H) {
 				if (urb_priv && ((td_list->index + 1)
 						< urb_priv->length)) {
-#ifdef OHCI_VERBOSE_DEBUG
-					dbg ("urb %p TD %p (%d/%d), patch ED",
-						td_list->urb, td_list,
+					struct urb *urb = td_list->urb;
+
+					/* help for troubleshooting: */
+					dbg ("urb %p usb-%s-%s ep-%d-%s "
+						    "(td %d/%d), "
+						    "cc %d --> status %d",
+						td_list->urb,
+						urb->dev->bus->bus_name,
+						urb->dev->devpath,
+						usb_pipeendpoint (urb->pipe),
+						usb_pipein (urb->pipe)
+						    ? "IN" : "OUT",
 						1 + td_list->index,
-						urb_priv->length);
-#endif
+						urb_priv->length,
+						cc, cc_to_error [cc]);
 					td_list->ed->hwHeadP = 
 			    (urb_priv->td [urb_priv->length - 1]->hwNextTD
 				    & __constant_cpu_to_le32 (TD_MASK))