On Fri, 28 Oct 2011, Vikram Pandita wrote:
> From: Vikram Pandita <vikram.pandita@xxxxxx>
>
> Data Buffer Error as per spec section 4.15.1.1.2
> results when there is Underrun or Overrun condition.
>
> This error is considered non-fatal and never gets reported.
> Its a very good indication on things going wrong at system level,
> like running memory at much slower speed.
>
> This is a good error to flag allowing system level corrections.
>
> An issue was found with OMAP4460 board where DDR had to be run
> at full speed and this logging helped.
Generally okay, but ...
> Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
> ---
> drivers/usb/host/ehci-q.c | 14 ++++++++++++++
> 1 files changed, 14 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
> index 4e4066c..2451361 100644
> --- a/drivers/usb/host/ehci-q.c
> +++ b/drivers/usb/host/ehci-q.c
> @@ -373,6 +373,20 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
> retry_xacterr:
> if ((token & QTD_STS_ACTIVE) == 0) {
>
> + /* Report Data Buffer Error: non-fatal but useful */
> + if (token & QTD_STS_DBE) {
> +
> + ehci_dbg(ehci,
> + "detected DataBufferErr %s for urb %p ep%d%s len %d, qtd %p [qh %p]\n",
> + (urb->ep->desc.bEndpointAddress & USB_DIR_IN) ?
> + "OVER-RUN" : "UNDER-RUN",
> + urb, urb->ep->desc.bEndpointAddress & 0x0f,
> + (urb->ep->desc.bEndpointAddress & USB_DIR_IN) ? "in" : "out",
You should use the usb_endpoint_dir_in() routine instead of open-coding
it. (Or, if you prefer, use usb_pipein(urb->pipe).) Similarly, use
usb_endpoint_num().
Also, what point is there in checking the direction twice? Get rid of
the OVER-RUN/UNDER-RUN part of the message; it doesn't add any new
information.
> + urb->transfer_buffer_length,
> + qtd, urb->ep->hcpriv);
> +
Unnecessary blank line here and above.
> + }
> +
Alan Stern
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