On Mon, Mar 25, 2002, Martin Diehl <[EMAIL PROTECTED]> wrote:
> On Thu, 21 Mar 2002, Johannes Erdfelt wrote:
>
> > > uhci.c: 3440: host controller process error. something bad happened
> >
> > This is what I was looking for.
>
> I'm getting exactly the same message with 2.5.7 when using irda-usb with
> uhci (but not with usb-uhci). And the host locks solid, not even reacting
> to any SysRq - but that's apparently not uhci's fault.
>
> What IMHO is an uhci problem however, is the special handling for
> USB_ZERO_PACKET: Looks like some typo, because I don't believe it's a good
> idea to send TD with bogus MaxLen field to the device ;-)
Doh! You're right, my fault. This is almost certainly the cause of the
HCPE.
> Furthermore, the decision when to add a zero-packet didn't cover all
> details.
>
> The patch below vs. 2.5.7 fixes (hope so) these issues. At least it makes
> the HCPE dissappear. irda-usb still isn't all that happy with it (in
> contrast to my private driver using USB_ZERO_PACKET as well) - but that's
> something to go on with Jean.
There's a slight bug in your fixed code. len will always be 0 at the end
of the previous loop, so your check will always incorrectly add the last
zero packet. Does this patch work correctly?
I've appended a corrected patch.
Thanks very much for troubleshooting this.
JE
--- linux-2.4.19-pre3.orig/drivers/usb/uhci.c Sun Mar 24 17:26:20 2002
+++ linux-2.4.19-pre3/drivers/usb/uhci.c Sun Mar 24 17:24:31 2002
@@ -1259,20 +1259,29 @@
data);
data += pktsze;
- len -= pktsze;
+ len -= maxsze;
usb_dotoggle(urb->dev, usb_pipeendpoint(urb->pipe),
usb_pipeout(urb->pipe));
} while (len > 0);
+ /*
+ * USB_ZERO_PACKET means adding a 0-length packet, if
+ * direction is OUT and the transfer_length was an
+ * exact multiple of maxsze, hence
+ * (len = transfer_length - N * maxsze) == 0
+ * however, if transfer_length == 0, the zero packet
+ * was already prepared above.
+ */
if (usb_pipeout(urb->pipe) && (urb->transfer_flags & USB_ZERO_PACKET) &&
- urb->transfer_buffer_length) {
+ !len && urb->transfer_buffer_length) {
td = uhci_alloc_td(uhci, urb->dev);
if (!td)
return -ENOMEM;
uhci_add_td_to_urb(urb, td);
- uhci_fill_td(td, status, destination | UHCI_NULL_DATA_SIZE |
+ uhci_fill_td(td, status, destination |
+ (UHCI_NULL_DATA_SIZE << 21) |
(usb_gettoggle(urb->dev, usb_pipeendpoint(urb->pipe),
usb_pipeout(urb->pipe)) << TD_TOKEN_TOGGLE),
data);
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