Hi Russell, On Jun 17, 2014, at 8:05 PM, Russell King - ARM Linux wrote: > On Tue, Jun 17, 2014 at 07:59:21PM +0300, Pantelis Antoniou wrote: >> That case might already work on FPGA people's trees. I know Altera for sure >> uses overlays, and some xilinx guys popped up on past discussions. >> Their vendor trees probably use an older revision of the patches. >> >> BTW, there is nothing special about DRM/v4l2 that can't be handled by >> a generic DT mechanism. What makes this such a big problem? > > Really? > > DRM is not hotpluggable in any shape or form, and David Airlie has > indicated that he does strongly opposes moving it in that direction. > > DRM follows the "card" model, where, at probe time, the hardware is > known and never changes until the "card" is torn down. No new > connectors can be added once the "card" is initialised, and no > connectors can be removed. Any changes must be done by tearing down > the entire card and reconstructing it (if reconstructing it with a > reduced set of hardware is appropriate.) > That is a limitation of the current DRM implementation. I seems to be this is born out of some kind of misunderstanding about how DT can (and does) support dynamic changes. I admit that I haven't done much work on DRM (besides some tinkering with Rob Clark's ti_lcdc DRM driver), but knowing what DT does have a dynamic change notifier support, perhaps it can be made to work. As I said, the next thing coming is transactional DT support, perhaps you can share the DT fragment describing your use-case (before/after) and I'll try to accommodate in the next patch series. Regards -- Pantelis > -- > FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly > improving, and getting towards what was expected from it. -- 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
