On 03/06/2005 18:38, Alan Stern wrote:
On Fri, 3 Jun 2005, Stuart MacDonald wrote:
I did see that uhci_interrupt() stops entering ie interrupts have
stopped being generated, but not due to lockup since the system was
fine, and I could reload my driver and have it communicate again.
That's the same as the symptoms I get using the ftdi_sio driver with uhci.o
However, there is one possibility... Older Intel UHCI hardware (the PIIX3
Neptune chipset) has an erratum that causes the controller sometimes to
update a completed TD's status but not update the QH's element pointer.
As a result the controller remains stuck on the completed TD and never
advances to the next one. Could that be happening to you? You can find
out by building the driver with CONFIG_USB_DEBUG turned on and loading it
with
I'm using VIA 3038 hardware, so the problem isn't specific to the Intel
Neptune chipset.
modprobe uhci debug=3
Then the file under /proc/driver/uhci/ corresponding to the controller in
use will contain debugging information showing the current state of the
schedule. If you examine that while the queue is stopped you'll be able
to see exactly what's wrong.
I'm not sure if I'd make head or tail of it, but I'll give that a go
sometime.
Of course this particular erratum would also affect transfers that don't
use bulk queuing...
Please don't spend any time on this on my behalf; I've already worked
around it.
Okay, I won't.
Don't blame you!
--
-=( Ian Abbott @ MEV Ltd. E-mail: <[EMAIL PROTECTED]> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
-------------------------------------------------------
This SF.Net email is sponsored by: NEC IT Guy Games. How far can you shotput
a projector? How fast can you ride your desk chair down the office luge track?
If you want to score the big prize, get to know the little guy.
Play to win an NEC 61" plasma display: http://www.necitguy.com/?r=20
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
