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. 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. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
