Commit 332960bd authored Oct 30, 2011 by Vikram Pandita Committed by Greg Kroah-Hartman Nov 14, 2011

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>

parent 4b6181ca

drivers/usb/host/ehci-q.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -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.
		*/

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