From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yakir Yang Subject: Re: [PATCH v3 06/14] Documentation: drm/bridge: add document for analogix_dp Date: Mon, 24 Aug 2015 20:48:01 +0800 Message-ID: <55DB1281.9070502@rock-chips.com> References: <1439995728-18046-1-git-send-email-ykk@rock-chips.com> <1439995834-18363-1-git-send-email-ykk@rock-chips.com> <55DA8486.1000803@rock-chips.com> <55DA9B72.1030804@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <55DA9B72.1030804@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Krzysztof Kozlowski , Rob Herring Cc: heiko@sntech.de, Sean Paul , Takashi Iwai , dri-devel , Andrzej Hajda , Gustavo Padovan , "linux-samsung-soc@vger.kernel.org" , Vincent Palatin , Kishon Vijay Abraham I , linux-rockchip@lists.infradead.org, Russell King , Thierry Reding , "devicetree@vger.kernel.org" , Pawel Moll , Ian Campbell , David Airlie , Doug Anderson , Inki Dae , Ajay kumar , Rob Herring , "linux-arm-kernel@lists.infradead.org" M List-Id: devicetree@vger.kernel.org Hi Krzysztof, =E5=9C=A8 08/24/2015 12:20 PM, Krzysztof Kozlowski =E5=86=99=E9=81=93: > On 24.08.2015 11:42, Yakir Yang wrote: >> Hi Krzysztof, >> >> =E5=9C=A8 08/23/2015 07:43 PM, Krzysztof Kozlowski =E5=86=99=E9=81=93= : >>> 2015-08-24 8:23 GMT+09:00 Rob Herring : >>>> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang w= rote: >>>>> Analogix dp driver is split from exynos dp driver, so we just >>>>> make an copy of exynos_dp.txt, and then simplify exynos_dp.txt >>>>> >>>>> Beside update some exynos dtsi file with the latest change >>>>> according to the devicetree binding documents. >>>> You can't just change the exynos bindings and break compatibility.= Is >>>> there some agreement with exynos folks to do this? >>> No, there is no agreement. This wasn't even sent to Exynos maintain= ers. >> Sorry about this one, actually I have add Exynos maintainers in vers= ion >> 1 & version 2, >> but lose some maintainers in version 3, I would fix it in bellow ver= sions. >> >>> Additionally the patchset did not look interesting to me because of >>> misleading subject - Documentation instead of "ARM: dts:". >>> >>> Yakir, please: >>> 1. Provide backward compatibility. Mark old properties as deprecate= d >>> but still support them. >> Do you mean that I should keep the old properties declare in exynos-= dp.txt, >> but just mark them as deprecated flag. > That is one of ways how to do this. However more important is that > driver should still support old bindings so such code: > - if (of_property_read_u32(dp_node, "samsung,color-space", > + if (of_property_read_u32(dp_node, "analogix,color-space", > > is probably wrong. Will the driver support old DTB in the same way as= it > was supporting before the change? Okay, I got your means. So document is not the focus, the most importan= t=20 is that driver should support the old dts prop. If so the new analogix dp drive= r=20 should keep the "samsung,color-space", rather then just mark it with [DEPRECATED] f= lag. But from your follow suggest, I think you agree to update driver code,=20 and just mark old prop with deprecated flag. If so I think such code would not be wro= ng - if (of_property_read_u32(dp_node, "samsung,color-space", + if (of_property_read_u32(dp_node, "analogix,color-space", And actually @Rob have suggest me to remove the prefix, just use=20 "color-space" here. > >> Let me show same examples, make >> me understand your suggest rightly. > exynos-dp already contains deprecated properties. Other ways of doing > this would be: > Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt > Documentation/devicetree/bindings/rtc/s3c-rtc.txt > > It depends up to you. The "touchscreen" looks good because it organiz= es > old properties in a common section. In case of exynos-dp.txt you can = add > at beginning of file information about new bindings and mark everythi= ng > deprecated. Whoops, thanks for your remind, I prefer the "touchscreen" style. >> 1. "samsung,ycbcr-coeff" is abandoned in latest analogix-dp driver, >> absolutely >> I should not carry this to analogix-dp.txt document. But I shou= ld >> keep this in >> exynos-dp.txt document, and mark them with an little "deprecate= d" flag. >> >> [Documentation/devicetree/bindings/video/exynos_dp.txt] >> Required properties for dp-controller: >> [...] >> -samsung,ycbcr-coeff (DEPRECATED): >> YCbCr co-efficients for input video. >> COLOR_YCBCR601 =3D 0, COLOR_YCBCR709 =3D 1 >> >> Is it right ? > Yes, this is right. > >>> 2. Separate all DTS changes to a separate patch, unless bisectabili= ty >>> would be hurt. Anyway you should prepare it in a such way that >>> separation would be possible without breaking bisectability. >> So I should separate this patch into two parts, one is name "Documen= t:", >> the other is "ARM: dts: ". > Yes. > >> Honestly, I don't understand what the "bisectability" means in this = case. > I was referring to bisectability in general. The patchset should be > fully bisectable which means that it does not introduce any issues > during "git bisect". This effectively means that at each intermediate > step (after applying each patch, one by one) every existing stuff wor= ks > the same as previously without any regression. Including booting with > old DTB. Oh, thanks for your careful explain, so I guess your first comment is=20 talking about the "bisectability" that if I only apply the 01 - 05 patches, kernel=20 could not bootup normally, cause driver need "analogix,color-space" but DTB only have=20 "samsung,color-space". > >>> 3. Use proper subject for the patch changing DTS. This is not >>> documentation change! >> Hmm... when I separate this patch into two parts, I though I can kee= p >> "Documentation" proper subject in this patch, and the other is the "= ARM: >> dts" >> proper subject. Am I right ? > Yes, you're right. > >>> 4. Please use script get_maintainers to obtain list of valid >>> maintainers and CC-them with at least cover letter and patches >>> requiring their attention. >> Yeah, thanks. > Sure. Now I found older versions of the patchset but previously there > were no changes to the bindings. Again the prefix in subject is > important to easily filter out and find necessary emails. > > BTW, I like the patchset because I like in general works which merge > code and reduce duplicate stuff. Aha, thanks :-D Best regards, - Yakir > Best regards, > Krzysztof > > > > >