Re: [PATCH v5 00/39] i.MX Media Driver

[Steve Longerbeam]

Hi Russell,


On 03/14/2017 10:29 AM, Steve Longerbeam wrote:
> 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.

Due to some fixes to ov5640 from version 4, v4l2_pipeline_pm APIs are 
working
now, so I've removed imx_media_pipeline_set_power() and switched to
v4l2_pipeline_pm_use() in capture device open/release and 
v4l2_pipeline_link_notify()
in imx_media_link_notify(), for the pipeline power management.

Steve