On Thu, Oct 03, 2013 at 06:00:50PM -0000, hema...@codeaurora.org wrote:
> We have devices which require to send zero length packet in data stage to
> host in certain cases. We were not seeing any issue when we were using
> ehci based controller. When we switched to XHCI here is what we are
> observing:-
> 
> For IN DATA dir control xfer XHCI sets ISP so xhci updates actual_length
> for short packet in data stage using event->transfer_len.
> 
> But for data packets not short xhci directly uses
> urb->transfer_buffer_length as actual_length.This is done assuming data
> stage will never have zero length (short packet) data packet. Once Device
> sends zero length packet in data stage
> ISP triggers and actual_length is updated with value 0. Then later in
> status stage (since urb->actual_length is zero) driver incorrectly sets
> actual_length with urb->transfer_buffer_length.
> 
> 
> I would like to get insight from  linux-usb grp to fix this issue.

What kernel version are you seeing these problems?

thanks,

greg k-h
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