Re: [PATCH v5 2/6] drm/bridge: Add a devm_ allocator for panel bridge.

[Noralf TrÃnnes]

(I had to switch to Daniel's Intel address to get this sent)

Den 05.08.2017 00.19, skrev Ilia Mirkin:
> On Fri, Aug 4, 2017 at 4:43 PM, Eric Anholt <eric@xxxxxxxxxx> wrote:
> > Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> writes:
> >
> > > Hi Eric,
> > >
> > > (CC'ing Daniel)
> > >
> > > Thank you for the patch.
> > >
> > > On Tuesday 18 Jul 2017 14:05:06 Eric Anholt wrote:
> > > > This will let drivers reduce the error cleanup they need, in
> > > > particular the "is_panel_bridge" flag.
> > > >
> > > > v2: Slight cleanup of remove function by Andrzej
> > > I just want to point out that, in the context of Daniel's work on hot-unplug,
> > > 90% of the devm_* allocations are wrong and will get in the way. All DRM core
> > > objects that are accessible one way or another from userspace will need to be
> > > properly reference-counted and freed only when the last reference disappears,
> > > which could be well after the corresponding device is removed. I believe this
> > > could be one such objects :-/
> > Sure, if you're hotplugging, your life is pain.  For non-hotpluggable
> > devices, like our SOC platform devices (current panel-bridge consumers),
> > this still seems like an excellent simplification of memory management.
> At that point you may as well make your module non-unloadable, and
> return failure when trying to remove a device from management by the
> driver (whatever the opposite of "probe" is, I forget). Hotplugging
> doesn't only happen when physically removing, it can happen for all
> kinds of reasons... and userspace may still hold references in some of
> those cases.

If drm_open() gets a ref on dev->dev and puts it in drm_release(),
won't that delay devm_* cleanup until userspace is done?