From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 762CFC7112F for ; Mon, 21 Jan 2019 11:49:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4EF3E2085A for ; Mon, 21 Jan 2019 11:49:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728162AbfAULtT (ORCPT ); Mon, 21 Jan 2019 06:49:19 -0500 Received: from metis.ext.pengutronix.de ([85.220.165.71]:37645 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727909AbfAULtT (ORCPT ); Mon, 21 Jan 2019 06:49:19 -0500 Received: from lupine.hi.pengutronix.de ([2001:67c:670:100:3ad5:47ff:feaf:1a17] helo=lupine) by metis.ext.pengutronix.de with esmtp (Exim 4.89) (envelope-from ) id 1glY4n-0002wv-BW; Mon, 21 Jan 2019 12:49:13 +0100 Message-ID: <1548071350.3287.3.camel@pengutronix.de> Subject: Re: [PATCH v3 1/2] media: imx: csi: Disable SMFC before disabling IDMA channel From: Philipp Zabel To: Steve Longerbeam , linux-media@vger.kernel.org Cc: Gael PORTAY , Peter Seiderer , stable@vger.kernel.org, Mauro Carvalho Chehab , Greg Kroah-Hartman , "open list:STAGING SUBSYSTEM" , open list Date: Mon, 21 Jan 2019 12:49:10 +0100 In-Reply-To: <20190119010457.2623-2-slongerbeam@gmail.com> References: <20190119010457.2623-1-slongerbeam@gmail.com> <20190119010457.2623-2-slongerbeam@gmail.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:100:3ad5:47ff:feaf:1a17 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Fri, 2019-01-18 at 17:04 -0800, Steve Longerbeam wrote: > Disable the SMFC before disabling the IDMA channel, instead of after, > in csi_idmac_unsetup(). > > This fixes a complete system hard lockup on the SabreAuto when streaming > from the ADV7180, by repeatedly sending a stream off immediately followed > by stream on: > > while true; do v4l2-ctl -d4 --stream-mmap --stream-count=3; done > > Eventually this either causes the system lockup or EOF timeouts at all > subsequent stream on, until a system reset. > > The lockup occurs when disabling the IDMA channel at stream off. Stopping > the video data stream entering the IDMA channel before disabling the > channel itself appears to be a reliable fix for the hard lockup. That can > be done either by disabling the SMFC or the CSI before disabling the > channel. Disabling the SMFC before the channel is the easiest solution, > so do that. > > Fixes: 4a34ec8e470cb ("[media] media: imx: Add CSI subdev driver") > > Suggested-by: Peter Seiderer > Reported-by: Gaël PORTAY > Signed-off-by: Steve Longerbeam Gaël, could we get a Tested-by: for this as well? > Cc: stable@vger.kernel.org > --- > Changes in v3: > - switch from disabling the CSI before the channel to disabling the > SMFC before the channel. > Changes in v2: > - restore an empty line > - Add Fixes: and Cc: stable > --- > drivers/staging/media/imx/imx-media-csi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c > index e18f58f56dfb..8610027eac97 100644 > --- a/drivers/staging/media/imx/imx-media-csi.c > +++ b/drivers/staging/media/imx/imx-media-csi.c > @@ -560,8 +560,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv) > static void csi_idmac_unsetup(struct csi_priv *priv, > enum vb2_buffer_state state) > { > - ipu_idmac_disable_channel(priv->idmac_ch); > ipu_smfc_disable(priv->smfc); > + ipu_idmac_disable_channel(priv->idmac_ch); Steve, do you have any theory why this helps? It's a bit weird to disable the SMFC module while the DMA channel is still enabled. I think this warrants a big comment, given that enable order is SMFC_EN before IDMAC channel enable. Also ipu_smfc_disable is refcounted, so if the other CSI is capturing simultaneously, this change has no effect. FWIW, I don't see any regressions though. regards Philipp