On 2014년 05월 08일 19:52, Ajay kumar wrote: > +Dave > +Thierry > > On Thu, May 8, 2014 at 1:14 PM, Inki Dae <inki.dae@xxxxxxxxxxx> wrote: >> >> Just re-sending with text mode. Sorry for this. >> >> >> On 2014년 05월 08일 15:41, Andrzej Hajda wrote: >>> On 05/05/2014 09:52 PM, Ajay Kumar wrote: >>>> This patchset is based on exynos-drm-next-todo branch of Inki Dae's tree at: >>>> git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos.git >>>> >>>> I have just put up Rob's and Sean's idea of chaining up the bridges >>>> in code, and have implemented basic panel controls as a chained bridge. >>>> This works well with ptn3460 bridge chip on exynos5250-snow board. >>>> >>>> Still need to make use of standard list calls and figure out proper way >>>> of deleting the bridge chain. So, this is just a rough version. >>> >>> As I understand this patchset tries to solve two things: >>> 1. Implement panel as drm_bridge, to ease support for hardware chains: >>> Crtc -> Encoder -> Bridge -> Panel >>> 2. Add support to drm_bridge chaining, to allow software chains: >>> drm_crtc -> drm_encoder -> drm_bridge -> drm_bridge,panel >>> >>> It is done using Russian doll schema, ops from the bridge calls the same >>> ops from the next bridge and the next bridge ops can do the same. >>> >>> This schema means that all the bridges including the last one are seen >>> from the drm core point of view as a one big drm_bridge. Additionally in >>> this particular case, the first bridge (ptn3460) implements connector >>> so it is hard to guess what is the location of the 2nd bridge in video >>> stream chain, sometimes it is after the connector, sometimes before. >>> All this is quite confusing. >>> >>> But if you look at the bridge from upstream video interface point of >>> view it is just a panel, edp panel in case of ptn3460, ie ptn3460 on its >>> video input side acts as a panel. On the output side it expects a panel, >>> lvds panel in this case. >>> >>> So why not implement ptn3460 bridge as drm_panel which internally uses >>> another drm_panel. With this approach everything fits much better. >>> You do not need those (pre|post)_(enable|disable) calls, you do not need >>> to implement connector in the bridge and you have a driver following >>> linux driver model. And no single bit changed in drm core. >>> >>> I have implemented this way DSI/LVDS bridge, it was sent as RFC [1][2]. >>> It was not accepted as Inki preferred drm_bridge but as I see the >> >> Yes, in above email threads, I disagreed to using drm_panel framework >> for bridge device, especially, to implement connector/encoder to crtc >> driver. >> >> However, I thought that it'd be more generic way that lvds drivers use >> driver-model, and the use of drm_panel infrastructure would be suitable >> to doing this. >> >> So my intention in turn, was that LVDS driver uses integrated drm_bridge >> based on drm_panel infrastructure[1], and RFC patch[2] for it. This way >> is same as your proposal in the point that LVDS and Panel drivers use >> driver-model. The only different point is that LVDS driver has some ops >> specific to LVDS device, not using existing ops of drm_panel commonly: >> we may need to consider the characteristic of LVDS device. >> >> [1]:http://www.spinics.net/lists/dri-devel/msg55555.html >> [2]:http://www.spinics.net/lists/dri-devel/msg55658.html >> >> Thanks, >> Inki Dae > I am just consolidating the discussion happening here. > 1) This patchset started from a discussion wherein I tried to combine > drm_panel with drm_bridge. > https://www.mail-archive.com/linux-samsung-soc@xxxxxxxxxxxxxxx/msg28943.html > 2) Sean and Rob suggested to implement a chain of bridges and then > consider adding > basic panel controls as a bridge. > 3) Andrej's idea is to drop the existing bridge infrastructure and > implement ptn3460 using drm_panel, > the same way he has implemented > http://permalink.gmane.org/gmane.linux.drivers.devicetree/61559. > 4) Inki's suggestion is to combine drm_bridge, drm_panel and > drm_enhance into a single > drm_hw_block. > And more thing, we would need to consider image enhancer device placed between crtc and connector/encoder devices. And it'd better to rename drm_hw_block to drm_bridge, and existing drm_bridge relevant codes should be removed. Thanks, Inki Dae > I am currently trying to implement (2):chaining of bridges, and I > think we have not yet > reached to a consensus. So adding few other people from drm community > to comment. > > Regards, > Ajay > >>> problems with drm_bridges I have decide to attract attention to much >>> more cleaner solution. >>> >>> [1]: http://permalink.gmane.org/gmane.linux.drivers.devicetree/61559 >>> [2]: http://permalink.gmane.org/gmane.linux.kernel.samsung-soc/27044 >>> >>> Regards >>> Andrzej >>> >>> >>>> >>>> Ajay Kumar (3): >>>> [RFC V2 1/3] drm: implement chaining of drm bridges >>>> [RFC V2 2/3] drm/bridge: add a dummy panel driver to support lvds bridges >>>> [RFC V2 3/3] drm/bridge: ptn3460: support bridge chaining >>>> >>>> .../bindings/drm/bridge/bridge_panel.txt | 45 ++++ >>>> drivers/gpu/drm/bridge/Kconfig | 6 + >>>> drivers/gpu/drm/bridge/Makefile | 1 + >>>> drivers/gpu/drm/bridge/bridge_panel.c | 240 +++++++++++++++++++++ >>>> drivers/gpu/drm/bridge/ptn3460.c | 21 +- >>>> drivers/gpu/drm/drm_crtc.c | 13 +- >>>> include/drm/bridge/bridge_panel.h | 37 ++++ >>>> include/drm/drm_crtc.h | 2 + >>>> 8 files changed, 360 insertions(+), 5 deletions(-) >>>> create mode 100644 Documentation/devicetree/bindings/drm/bridge/bridge_panel.txt >>>> create mode 100644 drivers/gpu/drm/bridge/bridge_panel.c >>>> create mode 100644 include/drm/bridge/bridge_panel.h >>>> >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
