Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754584AbbHYJld (ORCPT ); Tue, 25 Aug 2015 05:41:33 -0400 Received: from regular1.263xmail.com ([211.150.99.133]:37183 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751087AbbHYJla (ORCPT ); Tue, 25 Aug 2015 05:41:30 -0400 X-263anti-spam: KSV:0; X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-RL-SENDER: ykk@rock-chips.com X-FST-TO: andy.yan@rock-chips.com X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: ykk@rock-chips.com X-UNIQUE-TAG: <848619a0565eecabd527dc30094a1323> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Subject: Re: [PATCH v3 06/14] Documentation: drm/bridge: add document for analogix_dp To: Thierry Reding , Rob Herring References: <1439995728-18046-1-git-send-email-ykk@rock-chips.com> <1439995834-18363-1-git-send-email-ykk@rock-chips.com> <20150824125758.GA7557@n2100.arm.linux.org.uk> <20150825091246.GA14034@ulmo.nvidia.com> Cc: Russell King - ARM Linux , Heiko Stuebner , Jingoo Han , Fabio Estevam , Inki Dae , Joe Perches , Sean Paul , Takashi Iwai , dri-devel , Andrzej Hajda , Gustavo Padovan , "linux-samsung-soc@vger.kernel.org" , Vincent Palatin , linux-rockchip@lists.infradead.org, Kishon Vijay Abraham I , David Airlie , "devicetree@vger.kernel.org" , Pawel Moll , Ian Campbell , Doug Anderson , Rob Herring , "linux-arm-kernel@lists.infradead.org" , Mark Yao , "linux-kernel@vger.kernel.org" , Kyungmin Park , Daniel Kurtz , Philipp Zabel , Kumar Gala , Ajay kumar , Andy Yan From: Yakir Yang Message-ID: <55DC383F.4000103@rock-chips.com> Date: Tue, 25 Aug 2015 17:41:19 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150825091246.GA14034@ulmo.nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3575 Lines: 79 Hi Thierry, 在 2015/8/25 17:12, Thierry Reding 写道: > 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 >> 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 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/