Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751571Ab3FZMQe (ORCPT ); Wed, 26 Jun 2013 08:16:34 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:49597 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408Ab3FZMQc (ORCPT ); Wed, 26 Jun 2013 08:16:32 -0400 Message-ID: <51CADB9D.3070206@ti.com> Date: Wed, 26 Jun 2013 17:46:29 +0530 From: George Cherian User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: CC: , , , Subject: Re: [PATCH] usb: host: xhci-plat: Enable XHCI_SPURIOUS_SUCCESS quirk for xhci-plat References: <1372237137-17351-1-git-send-email-george.cherian@ti.com> <20130626090213.GQ12640@arwen.pp.htv.fi> In-Reply-To: <20130626090213.GQ12640@arwen.pp.htv.fi> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2351 Lines: 58 On 6/26/2013 2:32 PM, Felipe Balbi wrote: > Hi, > > On Wed, Jun 26, 2013 at 02:28:57PM +0530, George Cherian wrote: >> Synopsis xhci controllers with hci_version > 0.96 gives spurious success >> events on short packet completion. During webcam capture the >> "ERROR Transfer event TRB DMA ptr not part of current TD" was observed. >> The same application works fine with synopsis controllers hci_version 0.96. >> >> Signed-off-by: George Cherian >> --- >> drivers/usb/host/xhci-plat.c | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c >> index 93ad67e..e63c6d3 100644 >> --- a/drivers/usb/host/xhci-plat.c >> +++ b/drivers/usb/host/xhci-plat.c >> @@ -25,6 +25,16 @@ static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci) >> * dev struct in order to setup MSI >> */ >> xhci->quirks |= XHCI_BROKEN_MSI; >> + >> + /* >> + * In some xhci controllers which follows xhci 1.0 spec gives a spurious >> + * success event after a short transfer. This quirk will ignore such >> + * spurious event. Hit this issue in synopsis xhci controllers with >> + * hci_version > 0.96 >> + */ >> + >> + if (xhci->hci_version > 0x96) >> + xhci->quirks |= XHCI_SPURIOUS_SUCCESS; >> } > doesn't look like the correct way to do this. What if enabling that > quirk on hosts which don't have the quirk cause problems ? For a controller which does not have this issue will never get a spurious success for short packet ( and that too for only ISOCH). per this commit ad808333d Intel xhci: Ignore spurious successful event. This spurious successful event behavior isn't technically disallowed by the xHCI specification, so make the xHCI driver just ignore the spurious completion event. > I would suggest adding a platform_data which (in our case) dwc3 will > pass to xhci-plat. Then you can do proper revision detection of the > synopsys controller and set the quirk only on the failing hosts. > > BTW, do you have the STARS number for this errata ? No STARS number yet. Regards -George -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/