[OpenWrt-Devel] lantiq usb - isochronous transfers

Ben Mulvihill ben.mulvihill at gmail.com
Mon Nov 10 03:03:25 EST 2014

May I ask what the status of isochronous transfer support is
in the lantiq hcd driver? It was working in Attitude Adjustment
(at least my usb sound card worked anyway).
But a lot of changes were made to the driver between AA and BB,
including new code related to isosynchronous transfers, which are
now disabled by default (CONFIG_USB_HOST_IFX_WITH_ISO=n).
Someone else has filed a bug about this:


I tried building a BB image with isochronous transfers enabled,
but ifxhcd_intr.c failed to compile. The errors look like the
sorts of careless syntax errors which most people make when
writing a first version of a new piece of code, and my guess is
that this bit of code has have never in fact been compiled, let
alone tested. I have managed to get it to compile by making
various plausible corrections, but I don't yet have any sound.
Before I investigate further can you tell me whether it is
supposed to be working?

(Below, for reference, are the corrections I have made. But this
is just an initial attempt, certainly not a patch to be merged.)

Many thanks,

Ben Mulvihill

--- a/package/kernel/lantiq/ltq-hcd/src/ifxhcd_intr.c	2014-11-10 00:31:52.744641266 +0100
+++ b/package/kernel/lantiq/ltq-hcd/src/ifxhcd_intr.c	2014-11-10 00:25:03.321242453 +0100
@@ -103,6 +103,10 @@
 		ifxusb_mreg(&((_hc_regs_)->hcintmsk),0, hcintmsk.d32); \
 	} while (0)
+void init_hc(ifxhcd_epqh_t *_epqh);
  * Save the starting data toggle for the next transfer. The data toggle is
  * saved in the QH for non-control transfers and it's saved in the QTD for
@@ -4089,13 +4093,13 @@ void init_hc(ifxhcd_epqh_t *_epqh)
 				ifxhc->isoc_xact_pos = IFXUSB_HCSPLIT_XACTPOS_ALL;
-			_epqh->isoc_frame_index=0;
+			urbd->isoc_frame_index=0;
-			if(_urb->transfer_flags && URB_ISO_ASAP)
+			if(urb->transfer_flags && URB_ISO_ASAP)
-				_epqh->isoc_start_frame=_urb->start_frame;
+				_epqh->isoc_start_frame=urb->start_frame;
 			#ifdef __EN_ISOC_SPLIT__
 				_epqh->isoc_split_pos   =0;
@@ -4296,8 +4300,8 @@ void select_eps_sub(ifxhcd_hcd_t *_ifxhc
 								list_add_tail(&epqh->ql, &_ifxhcd->epqh_list_isoc);
-								urbd->phase==URBD_ACTIVE;
-								epqh->hc.phase=HC_WAITING;
+								urbd->phase=URBD_ACTIVE;
+								epqh->hc->phase=HC_WAITING;
 								ifxhcd_hc_start(_ifxhcd, epqh->hc);
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