Re: [PATCH v2 15/17] rcar-vin: register the video device at probe time

["Niklas Söderlund" <niklas.soderlund@ragnatech.se>]

Hi Hans,

On 2017-05-29 09:55:07 +0200, Hans Verkuil wrote:
> On 05/29/2017 09:49 AM, Niklas Söderlund wrote:
> > Hi Hans,
> > 
> > Thanks for taking the time to look at this :-)
> > 
> > On 2017-05-29 08:56:31 +0200, Hans Verkuil wrote:
> > > On 05/29/2017 08:52 AM, Hans Verkuil wrote:
> > > > Hi Niklas,
> > > > 
> > > > On 05/24/2017 02:15 AM, Niklas Söderlund wrote:
> > > > > From: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > > > > 
> > > > > The driver registers the video device from the async complete callback
> > > > > and unregistered in the async unbind callback. This creates problems if
> > > > > if the subdevice is bound, unbound and later rebound. The second time
> > > > > video_register_device() is called it fails:
> > > > > 
> > > > >       kobject (eb3be918): tried to init an initialized object, something is seriously wrong.
> > > > > 
> > > > > To prevent this register the video device at prob time and don't allow
> > > > > user-space to open the video device if the subdevice have not yet been
> > > > > bound.
> > > > 
> > > > This patch feels wrong. Creating the video device in the notify_complete seems
> > > > right to me, so the problem is much more likely in the removal of the video device.
> > > > 
> > > > What *exactly* goes wrong here
> > 
> > When calling video_register_device() it fails since the device structure
> > have already been registered once. So it is not possible to register,
> > unregister and then register the same video device struct. The other
> > solution to this is to memset the whole embedded video device struct to
> > zero  before initializing it and calling video_register_device(), but
> > that feels more wrong. Let me know what you think and I will rework this
> > patch.
> > 
> > 
> > > > 
> > > > FYI: I'm taking all other patches of this series,
> > > 
> > > Oops, I saw Sakari had two comments. I'll wait for a v3 then.
> > > 
> > > If you make a v3 with Sakari's suggestions and drop this patch, then I can merge
> > > it and make a pull request for it.
> > 
> > I can't find Sakaris comments in my inbox or on the ML for this thread.
> > Where did you see them?
> 
> Sorry, my mistake. Those comments were for the
> 
> "[PATCH v2 0/2] media: entity: add operation to help map DT node to media pad"
> 
> patch series.
> 
> Never mind. I'm going to merge all but this patch and get back to you on this one.

Thanks!

> 
> Regards,
> 
> 	Hans

-- 
Regards,
Niklas Söderlund