From mboxrd@z Thu Jan 1 00:00:00 1970 From: slongerbeam@gmail.com (Steve Longerbeam) Date: Tue, 14 Mar 2017 10:29:07 -0700 Subject: [PATCH v5 00/39] i.MX Media Driver In-Reply-To: <20170312210952.GV21222@n2100.armlinux.org.uk> 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> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 at 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