On Sat, 29 Oct 2011, Vikram Pandita wrote:

> From: Vikram Pandita <[email protected]>
> 
> 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.
> 
> Signed-off-by: Vikram Pandita <[email protected]>
> Reviewed-by: Marek Vasut <[email protected]>
> ---
> v1: original patch
> 
> v2: fix review comments from Alan Stern<[email protected]>

I'm sorry, there was one more thing that I forgot to mention last time.

>  drivers/usb/host/ehci-q.c |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
> index 4e4066c..f81c6de 100644
> --- a/drivers/usb/host/ehci-q.c
> +++ b/drivers/usb/host/ehci-q.c
> @@ -373,6 +373,16 @@ 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 for urb %p ep%d%s len 
> %d, qtd %p [qh %p]\n",
> +                             urb, usb_endpoint_num(urb->ep),
> +                             usb_endpoint_dir_in(urb->ep) ? "in" : "out",
> +                             urb->transfer_buffer_length,
> +                             qtd, urb->ep->hcpriv);

Don't use urb->ep->hcpriv; use qh instead.  Also, the continuation 
lines should be indented relative to the start of the statement.

Alan Stern

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