From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Agner Date: Mon, 18 Jun 2018 08:13:16 +0000 Subject: Re: [PATCH 1/3] drm: mxsfb: Change driver.name to mxsfb-drm Message-Id: <85308177b3679d1103feee7a2b6e5879@agner.ch> List-Id: References: <47ea7572011735b68a8a70f0e11bdf00cb2fd86a.1529091248.git.leonard.crestez@nxp.com> <07be6d9a85b6be655fc2b084be81d8bf9715b57a.camel@nxp.com> <638457fd-85da-8fec-d146-517c43f71813@denx.de> <6995fa4b-47a9-887b-5e4f-4284ca6a2c79@gmail.com> <20180618074320.GS3438@phenom.ffwll.local> In-Reply-To: <20180618074320.GS3438@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Marek Vasut , Daniel Vetter , Sascha Hauer Cc: marex@denx.de, devicetree@vger.kernel.org, linux-fbdev@vger.kernel.org, marcofrk@gmail.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, dl-linux-imx , kernel@pengutronix.de, Fabio Estevam , Leonard Crestez , shawnguo@kernel.org, linux-arm-kernel@lists.infradead.org On 18.06.2018 09:43, Daniel Vetter wrote: > On Sat, Jun 16, 2018 at 01:32:44AM +0200, Marek Vasut wrote: >> On 06/16/2018 12:42 AM, Leonard Crestez wrote: >> > On Fri, 2018-06-15 at 23:36 +0200, Marek Vasut wrote: >> >> On 06/15/2018 10:58 PM, Leonard Crestez wrote: >> >>> On Fri, 2018-06-15 at 16:47 -0300, Fabio Estevam wrote: >> >>>> On Fri, Jun 15, 2018 at 4:43 PM, Leonard Crestez >> >>>> wrote: >> > >> >>>>> The FBDEV driver uses the same name and both can't be registered at the >> >>>>> same time. Fix this by renaming the drm driver to mxsfb-drm >> >>>> >> >>>> Stefan sent the same patch a few days ago: >> >>> >> >>> In that thread there is a proposal for removing the old fbdev/mxsfb >> >>> driver entirely. >> >>> >> >>> That would break old DTBs, isn't this generally considered bad? Also, >> >>> are we sure the removal of fbdev/mxsfb wouldn't lose any features? >> >>> >> >>> What my series does is make both drivers work with the same kernel >> >>> image and turns the choice into a board-level dtb decision. Supporting >> >>> everything at once seems desirable to me and it allows for a very >> >>> smooth upgrade path. >> >> >> >> Having two drivers in the kernel with different set of bugs is always bad. >> >> >> >>> The old driver could be removed later, after all users are converted. >> >> >> >> Both drivers were in for long enough already. And let's be realistic, >> >> how many MX23/MX28 users of old DTs with new kernels are there who >> >> cannot update the DT as well ? >> > >> > Grepping for "display =" in arch/arm/boot/dts/imx* I see that old >> > bindings are also used by 3rd-party boards for imx6/7: >> > * imx6sx-nitrogen6sx >> > * imx6ul-geam >> > * imx6ul-isiot >> > * imx6ul-opos6uldev >> > * imx6ul-pico-hobbit >> > * imx6ul-tx6ul >> > * imx7d-nitrogen7 >> >> Er, yes, a handful of boards which could be updated :) >> >> > Converting everything might be quite a bit of work, and explicitly >> > supporting old bindings is also work. >> >> Does adding support for old bindings justify the effort invested ? I >> doubt so, it only adds more code to maintain. >> >> > It is very confusing that there is a whole set of displays for imx6/7 >> > which are supported by upstream but only with a non-default config. >> > While it is extremely common in the embedded field to have custom >> > configs the default one in the kernel should try to "just work". >> > >> > Couldn't this patch series be considered a bugfix? It was also >> > surprisingly small. >> >> I think it's just a workaround which allows you to postpone the real >> fix, and I don't like that. > > Yeah agreed, imo the proper fix here would be to either update the dts for > the affected boards and/or make mxsfb accept the old dt bindings for > backwards compat. Artificially extending the life of the fbdev drivers > seems silly. We shouldn't have merged a DRM driver with a driver name which conflicts with an existing driver... If anything, this is artificially shortening the lifetime of the fbdev driver :-) Again, I am ok with removing the driver. I just think it is silly to do it just because of the conflicting driver name. Maybe Sascha, original author of the mxs fbdev driver has an opinion on this? -- Stefan