On Sun, 30 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.
>
> Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
> Reviewed-by: Marek Vasut <marek.vasut@xxxxxxxxx>
> Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
> ---
> v1: original patch
>
> v2: fix review comments from Alan Stern
> * use usb_endpoint_num, usb_endpoint_dir_in
>
> v3: More comments from Alan Stern
> * indent, use qh
>
> drivers/usb/host/ehci-q.c | 11 +++++++++++
> 1 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
> index 4e4066c..f136f7f1 100644
> --- a/drivers/usb/host/ehci-q.c
> +++ b/drivers/usb/host/ehci-q.c
> @@ -373,6 +373,17 @@ 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->desc),
> + usb_endpoint_dir_in(&urb->ep->desc) ? "in" : "out",
> + urb->transfer_buffer_length,
> + qtd,
> + qh);
> +
> /* on STALL, error, and short reads this urb must
> * complete and all its qtds must be recycled.
> */
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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