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USB: ehci: report Data Buffer Error in debug mode 

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@ti.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Vikram Pandita 2011-10-30 12:55:09 -07:00 committed by Greg Kroah-Hartman
parent 4b6181caa4
commit 332960bd7e
1 changed files with 11 additions and 0 deletions
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11
drivers/usb/host/ehci-q.c
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@ -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.
*/