2014-03-18 22:29 GMT+09:00 Rob Clark robdclark@gmail.com:
On Tue, Mar 18, 2014 at 8:58 AM, Inki Dae inki.dae@samsung.com wrote:
2014-03-18 21:47 GMT+09:00 Daniel Vetter daniel@ffwll.ch:
On Tue, Mar 18, 2014 at 1:42 PM, Inki Dae inki.dae@samsung.com wrote:
I think now drm_bridge couldn't do what we want for embedded systems as long as drm_encoder has drm_bridge. See the blow hardware pipeline, Display Controller-----Image Enhancement chip-----MIP DSI-----MIPI TO LVDS Bridge-----LCD Panel
In above hardware pipeline, Display controller is controlled by crtc, and Image Enhancement chip receives output from display controller. So the use of existing drm_bridge would be suitable to only bridge devices between MIPI DSI and LCD Panel, but not to Image Enhancement chip.
For such hardware, drm_panel infrastructure is more reasonable to me, and that is why I try to integrate drm_panel and drm_bridge to one integrated framework which has infrastructure same as existing drm_panel. The important thing is to free this integrated framework from drm_encoder so that crtc device can also use this framework.
Hm, what is this image enhancement chip? Is that some IP block on the SoC? Is it optional? Can it be attached to different crtcs?
In case of Exynos, this chip is in SoC, and can be only attached to one crtc, display controller. But I'm not sure other SoC have similar chip.
I think we have similar things on intel hardware, but without details on what it does and how it works I can't really say how to best expose it to userspace and how to best handle it internally in the driver. -Daniel
Simply saying, the image enhancement chip can enhance image data from display controller, i.e. saturation enhancement, color reproduction, dithering, and so on. And this chip receives image data through hardware wired lines connected internally between display controller and this chip.
I suppose in some sense it doesn't really matter if it is internal block or external chip..
but I'm still a bit confused about why you think drm_panel is a better fit.. could you explain that part?
As I already mentioned, see the below hardware pipeline, Display Controller-----Image Enhancement chip-----MIPI DSI-----MIPI TO LVDS Bridge-----LCD Panel
In above pipeline, the only place drm_bridge can exist is in MIPI DSI driver because drm_encoder and drm_connector should be implemented in MIPI DSI driver like we did using super node, at least in case of exynos - it seems that this way is reasonable to me according to super device and video-interface document.
However, there could be Image Enhancement chip between display controller and MIPI DSI, and that means we need other thing for controlling this chip because existing drm_bridge cannot be used for this. In the other hands, drm_panel infrastructure could be used by all device types, crtc or encoder/connector because drm_panel could belong to any device types. So I thought it'd better to use existing framework with a little change than using new one, and we could integrate these two frameworks, drm_bridge and drm_panel to one framework.
I am planning to integrate them to one framework, and remove existing drm_bridge. As a result, it would exist only one integrated drm_bridge.
Is there any way that can control such chip using existing drm_bridge contained in drm_encoder? if other better way, please give me your idea.
Thanks, Inki Dae
BR, -R
Thanks, Inki Dae
-- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
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