On Wednesday 01 June 2005 6:08 am, Patrick Boettcher wrote:
> Hi,
>
> On Tue, 31 May 2005, David Brownell wrote:
> >> However, I have a "new" problem. Since transfers are now taking place
> >> (URBs are submitted and received) every iso_frame_desc has status -71
> >> (-EPROTO) instead of being successful
> >
> > Was that _with_ the patch I pointed out to you?
>
> Ehm, which patch?
This one, now in the MM tree. I'm not sure it'd explain _every_ frame
getting an error, though according to your sample code you'll need this.
That is, you probably have something else going wrong too ... maybe the
wrong endpoint, or altsetting, is making the "gimme your ISO bits" request
fail.
(I think the "point out" email may have gotten garbaged due to some
email problems, sorry.)
- Dave
> > Given this is high speed, the conclusion is that you're getting
> > some kind of transaction error (XACTERR) on each request. Have
> > a look at the EHCI spec to see why you might be getting those.
>
> Will see if I catch it :) ?
>
> Thanks,
> Patrick.
>
The itd_patch() function is responsible for allocating entries in the
buffer page pointer list of the iTD. Particularly, a new page pointer
is needed every time when buffer data crosses a page boundary.
However, there is a bug in the allocation logic: the function does not
allocate a new entry when the current transaction is the first
transaction in the iTD (as indicated by first!=0).
The consequence is that, when the data of the first transaction begins
somewhere at the end of a page so that it actually does cross the page
boundary, no new page pointer is allocated. This means that the data
at the end of the first transaction (beyond the page boundary) will be
accessed by the HC using the second page pointer, which is zero.
Furthermore, the first page pointer will be later overwritten by the
page pointers of the other transactions, which will garble it because
the value is or-ed into the iTD field.
All this particular check (for !first) does is cause incorrect
behaviour, so it should be entirely removed (and with it the variable
first that is not used for anything else).
Signed-off-by: Clemens Ladisch <[EMAIL PROTECTED]>
Signed-off-by: David Brownell <[EMAIL PROTECTED]>
--- g26.orig/drivers/usb/host/ehci-sched.c 2005-05-28 10:32:27.000000000 -0700
+++ g26/drivers/usb/host/ehci-sched.c 2005-05-28 10:41:06.000000000 -0700
@@ -637,9 +637,8 @@ iso_stream_alloc (int mem_flags)
{
struct ehci_iso_stream *stream;
- stream = kmalloc(sizeof *stream, mem_flags);
+ stream = kcalloc(1, sizeof *stream, mem_flags);
if (likely (stream != NULL)) {
- memset (stream, 0, sizeof(*stream));
INIT_LIST_HEAD(&stream->td_list);
INIT_LIST_HEAD(&stream->free_list);
stream->next_uframe = -1;
@@ -894,7 +893,7 @@ itd_sched_init (
trans |= length << 16;
uframe->transaction = cpu_to_le32 (trans);
- /* might need to cross a buffer page within a td */
+ /* might need to cross a buffer page within a uframe */
uframe->bufp = (buf & ~(u64)0x0fff);
buf += length;
if (unlikely ((uframe->bufp != (buf & ~(u64)0x0fff))))
@@ -1194,6 +1193,7 @@ itd_init (struct ehci_iso_stream *stream
{
int i;
+ /* it's been recently zeroed */
itd->hw_next = EHCI_LIST_END;
itd->hw_bufp [0] = stream->buf0;
itd->hw_bufp [1] = stream->buf1;
@@ -1210,8 +1210,7 @@ itd_patch (
struct ehci_itd *itd,
struct ehci_iso_sched *iso_sched,
unsigned index,
- u16 uframe,
- int first
+ u16 uframe
)
{
struct ehci_iso_packet *uf = &iso_sched->packet [index];
@@ -1228,7 +1227,7 @@ itd_patch (
itd->hw_bufp_hi [pg] |= cpu_to_le32 ((u32)(uf->bufp >> 32));
/* iso_frame_desc[].offset must be strictly increasing */
- if (unlikely (!first && uf->cross)) {
+ if (unlikely (uf->cross)) {
u64 bufp = uf->bufp + 4096;
itd->pg = ++pg;
itd->hw_bufp [pg] |= cpu_to_le32 (bufp & ~(u32)0);
@@ -1257,7 +1256,7 @@ itd_link_urb (
struct ehci_iso_stream *stream
)
{
- int packet, first = 1;
+ int packet;
unsigned next_uframe, uframe, frame;
struct ehci_iso_sched *iso_sched = urb->hcpriv;
struct ehci_itd *itd;
@@ -1290,7 +1289,6 @@ itd_link_urb (
list_move_tail (&itd->itd_list, &stream->td_list);
itd->stream = iso_stream_get (stream);
itd->urb = usb_get_urb (urb);
- first = 1;
itd_init (stream, itd);
}
@@ -1298,8 +1296,7 @@ itd_link_urb (
frame = next_uframe >> 3;
itd->usecs [uframe] = stream->usecs;
- itd_patch (itd, iso_sched, packet, uframe, first);
- first = 0;
+ itd_patch (itd, iso_sched, packet, uframe);
next_uframe += stream->interval;
stream->depth += stream->interval;
