[PATCH 1/3] video: fbdev: omap2: omapfb: remove __exit annotation

Felipe Balbi balbi at ti.com
Wed Oct 15 08:54:11 PDT 2014


On Wed, Oct 15, 2014 at 06:43:40PM +0300, Tomi Valkeinen wrote:
> >> Somehow omapfb device is still unbound from the driver, as I can then
> >> bind it again, causing probe to be called. Which breaks everything.
> >>
> >> I would've thought that unbinding is not possible if remove is missing,
> >> but that doesn't seem to be the case. I guess it just means that remove
> >> is not called when the driver & device are unbound.
> > 
> > if no remove it provided on platform_driver structure, platform bus
> > assumes you have nothing to do on your ->remove(), so you end up leaking
> > all resources you allocated on ->probe() (unless you *really* don't need
> > to do anything on ->remove).
> Yep. That's quite odd, still. grep shows quite many uses of __exit_p(),
> and all for remove callback. So, if you have something to release in
> remove(), you should set it always, for both module and built-in. And if
> you don't have anything to release, you would always just set .release
> to NULL.
> I mean, what's the use case for __exit_p()? With a quick glance, at
> least some of the other users also use __exit_p() the same way omapdss
> does (i.e. in the wrong way).

__exit_p() meant something else a few years back, perhaps those were
left over from some tree-wide cleanups.

> >> We have 18 __exit_p()s in omapdss and related drivers. I guess they are
> >> all broken the same way.
> > 
> > yup, I should've grepped.
> > 
> >> Note that omapfb unbind & bind does not work even with this patch, but
> >> results in a crash as some old state is left into omapdss. The same
> >> happens also with unloading and loading omapfb module (but keeping
> >> omapdss module loaded).
> > 
> > It worked fine for me. I unbound and bound omapfb multiple times.
> Hmm, ok. Odd, the bug was quite clear and I think it should happen every
> time. Well, I was using omap4. If you used AM4xx, that's basically omap3
> DSS. Maybe there's a diff there.

could very well be :-)

> >> So there seems to be more issues around this.
> > 
> > quite a few more, I'd say
> Yep, I'll have a look at this.


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