[RFC 00/15] Resource tracking/allocation framework

[A H]

10 gru 2014 17:16 "Russell King - ARM Linux" <linux at arm.linux.org.uk>
napisał(a):
>
> On Wed, Dec 10, 2014 at 04:48:18PM +0100, Andrzej Hajda wrote:
> > 3. There are drivers which can work without specific resource, but if
> >   the resource becomes available/unavailable it can do some additional
stuff.
> >   An example of such driver is DRM driver (more precisely
drm_connector) -
> >   it can start without attached drm_panel, but if the panel becomes
available it
> >   can react by generating HPD event and start using it.
>
> Bad example, and actually incorrect.  DRM connectors are referenced in
> userspace by an IDR number, which can be re-used in the case of a
> connector appearing, disappearing, and then a different connector
> re-appearing.

But it is not about reappearing of drm_connector, it is about reappearing
of drm_panel which is fortunately not a part of drm driver. Connector here
is only consumer of drm_panel which should have possibility to receive
notifications on panel (dis-)appearance.

Regards
Andrzej

>
> DRM really is *not* safe to hotplug like this: DRM is more a card-level
> thing, which is why we have the component helpers - which allow us to
> merge several devices into one logical card-like device in a generic
> manner.
>
> DRM needs a stable picture of the CRTCs, encoders and connectors, which
> should _never_ change during the lifetime of the DRM device.  Devices
> attached to connectors can be hotplugged, but that's about the limit of
> hot-plugging in DRM.
>
> --
> FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
> according to speedtest.net.
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