Hi Thierry, å¨ 2015/8/25 17:12, Thierry Reding åé: > On Mon, Aug 24, 2015 at 09:48:27AM -0500, Rob Herring wrote: >> On Mon, Aug 24, 2015 at 7:57 AM, Russell King - ARM Linux >> <linux at arm.linux.org.uk> wrote: >>> On Sun, Aug 23, 2015 at 06:23:14PM -0500, Rob Herring wrote: >>>> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang <ykk at rock-chips.com> wrote: >>>>> + -analogix,color-depth: >>>>> + number of bits per colour component. >>>>> + COLOR_6 = 0, COLOR_8 = 1, COLOR_10 = 2, COLOR_12 >>>>> = 3 >>>> This seems pretty generic. Just use 6, 8, 10, or 12 for values. And >>>> drop the vendor prefix. >>> Please think about this some more. What does "color-depth" mean? Does it >>> mean the number of bits per colour _component_, or does it mean the total >>> number of bits to represent a particular colour. It's confusing as it >>> stands. >> Then "component-color-bpp" perhaps? > There should be no need to have this in DT at all. The BPC is a property > of the attached panel and it should come from the panel (either the > panel driver or parsed from EDID if available).
Actually I have send an email about this one to you in version 2, just past from that email: "samsung,color_space" and "samsung,color-depth" The drm_display_info's color_formats and bpc indicate the monitor display ability, but the edp driver could not take it as input video format directly. For example, with my DP TV I would found "RGB444 & YCRCB422 & & YCRCB444" support in drm_display_info.color_formats and 16bit bpc support, but RK3288 crtc driver could only output RGB & ITU formats, so finally analogix_dp-rockchip driver config crtc to RGBaaa 10bpc mode. In this sutiation, the analogix_dp core driver would pazzled by the drm_display_info, can't chose the right color_space and bpc. And this is the place that confused me, wish you could give some ideas about this one :-) - Yakir >>> When we adopted the graph bindings for iMX DRM, I thought exactly at that >>> time "it would be nice if this could become the standard for binding DRM >>> components together" but I don't have the authority from either the DT >>> perspective or the DRM perspective to mandate that. Neither does anyone >>> else. That's the _real_ problem here. >>> >>> I've seen several DRM bindings go by which don't use the of-graph stuff, >>> which means that they'll never be compatible with generic components >>> which do use the of-graph stuff. >> It goes beyond bindings IMO. The use of the component framework or not >> has been at the whim of driver writers as well. It is either used or >> private APIs are created. I'm using components and my need for it >> boils down to passing the struct drm_device pointer to the encoder. >> Other components like panels and bridges have different ways to attach >> to the DRM driver. > I certainly support unification, but it needs to be reasonable. There > are cases where a different structure for the binding work better than > another and I think this always needs to be evaluated on a case by case > basis. > > Because of that I think it makes sense to make all these framework bits > opt-in, otherwise we could easily end up in a situation where drivers > have to be rearchitected (or even DT bindings altered!) in order to be > able to reuse code. > > Thierry