From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCH] usb: ehci: report Data Buffer Error in debug mode Date: Sat, 29 Oct 2011 02:22:22 +0200 Message-ID: <201110290222.22990.marek.vasut@gmail.com> References: <1319846874-10106-1-git-send-email-vikram.pandita@ti.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:35993 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755945Ab1J2AWZ (ORCPT ); Fri, 28 Oct 2011 20:22:25 -0400 In-Reply-To: <1319846874-10106-1-git-send-email-vikram.pandita@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Vikram Pandita Cc: stern@rowland.harvard.edu, linux-usb@vger.kernel.org, linux-omap@vger.kernel.org > From: Vikram Pandita > > 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 > --- > 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", > + urb->transfer_buffer_length, > + qtd, urb->ep->hcpriv); > + > + } > + > /* on STALL, error, and short reads this urb must > * complete and all its qtds must be recycled. > */ Looks basically ok to me. Reviewed-by: Marek Vasut