Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752777AbdCNR3Q (ORCPT ); Tue, 14 Mar 2017 13:29:16 -0400 Received: from mail-pg0-f68.google.com ([74.125.83.68]:35121 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752105AbdCNR3N (ORCPT ); Tue, 14 Mar 2017 13:29:13 -0400 Subject: Re: [PATCH v5 00/39] i.MX Media Driver To: Russell King - ARM Linux References: <1489121599-23206-1-git-send-email-steve_longerbeam@mentor.com> <20170312175118.GP21222@n2100.armlinux.org.uk> <191ef88d-2925-2264-6c77-46647394fc72@gmail.com> <20170312192932.GQ21222@n2100.armlinux.org.uk> <58b30bca-20ca-d4bd-7b86-04a4b8e71935@gmail.com> <20170312204037.GU21222@n2100.armlinux.org.uk> <20170312210952.GV21222@n2100.armlinux.org.uk> Cc: mark.rutland@arm.com, andrew-ct.chen@mediatek.com, minghsiu.tsai@mediatek.com, nick@shmanahar.org, songjun.wu@microchip.com, hverkuil@xs4all.nl, pavel@ucw.cz, shuah@kernel.org, devel@driverdev.osuosl.org, markus.heiser@darmarIT.de, Steve Longerbeam , robert.jarzmik@free.fr, geert@linux-m68k.org, p.zabel@pengutronix.de, linux-media@vger.kernel.org, devicetree@vger.kernel.org, kernel@pengutronix.de, arnd@arndb.de, tiffany.lin@mediatek.com, bparrot@ti.com, robh+dt@kernel.org, horms+renesas@verge.net.au, mchehab@kernel.org, laurent.pinchart+renesas@ideasonboard.com, linux-arm-kernel@lists.infradead.org, niklas.soderlund+renesas@ragnatech.se, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, jean-christophe.trotin@st.com, sakari.ailus@linux.intel.com, fabio.estevam@nxp.com, shawnguo@kernel.org, sudipm.mukherjee@gmail.com From: Steve Longerbeam Message-ID: Date: Tue, 14 Mar 2017 10:29:07 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170312210952.GV21222@n2100.armlinux.org.uk> Content-Type: text/plain; charset=windows-1252; 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: 2310 Lines: 50 On 03/12/2017 02:09 PM, Russell King - ARM Linux wrote: > On Sun, Mar 12, 2017 at 08:40:37PM +0000, Russell King - ARM Linux wrote: >> On Sun, Mar 12, 2017 at 01:36:32PM -0700, Steve Longerbeam wrote: >>> But hold on, if my logic is correct, then why did the CSI power-off >>> get reached in your case, multiple times? Yes I think there is a bug, >>> link_notify() is not checking if the link has already been disabled. >>> I will fix this. But I'm surprised media core's link_notify handling >>> doesn't do this. >> Well, I think there's something incredibly fishy going on here. I >> turned that dev_dbg() at the top of the function into a dev_info(), >> and I get: >> >> root@hbi2ex:~# dmesg |grep -A2 imx-ipuv3-csi >> [ 53.370949] imx-ipuv3-csi imx-ipuv3-csi.0: power OFF >> [ 53.371015] ------------[ cut here ]------------ >> [ 53.371075] WARNING: CPU: 0 PID: 1515 at drivers/staging/media/imx/imx-media-csi.c:806 csi_s_power+0xb8/0xd0 [imx_media_csi] >> -- >> [ 53.372624] imx-ipuv3-csi imx-ipuv3-csi.0: power OFF >> [ 53.372637] ------------[ cut here ]------------ >> [ 53.372663] WARNING: CPU: 0 PID: 1515 at drivers/staging/media/imx/imx-media-csi.c:806 csi_s_power+0xb8/0xd0 [imx_media_csi] >> >> There isn't a power on event being generated before these two power >> off events. I don't see a power on event even when I attempt to >> start streaming either (which fails due to the lack of bayer >> support.) > Found it - my imx219 driver returns '1' from its s_power function when > powering up, which triggers a bug in your code - when imx_media_set_power() > fails to power up, you call imx_media_set_power() telling it to power > everything off - including devices that are already powered off. Yep, there's a bug in the error cleanup in imx_media_pipeline_set_power(). On error, it needs to backout by calling s_power(off) as it is doing, but not through the whole pipeline, but needs to stop at the subdev encountered just before the subdev that failed. This was causing the s_power() imbalance. I will fix. > > This is really bad news - s_power() may be called via other paths, > such as when the subdev is opened. I don't think that is a problem, as long as power_count is working as it should, and the caller from the other paths has not created an imbalance. Steve