Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932653AbcJUMT6 (ORCPT ); Fri, 21 Oct 2016 08:19:58 -0400 Received: from mail-lf0-f65.google.com ([209.85.215.65]:35500 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753916AbcJUMT4 (ORCPT ); Fri, 21 Oct 2016 08:19:56 -0400 Date: Fri, 21 Oct 2016 14:19:51 +0200 From: Daniel Vetter To: Jani Nikula Cc: Andrzej Hajda , Emil Velikov , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "Sun, Jing A" , "Vetter, Daniel" , Thierry Reding Subject: Re: [PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate". Message-ID: <20161021121951.GW20761@phenom.ffwll.local> Mail-Followup-To: Jani Nikula , Andrzej Hajda , Emil Velikov , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "Sun, Jing A" , "Vetter, Daniel" , Thierry Reding References: <87h98ktxow.fsf@intel.com> <87lgxvqlg3.fsf@intel.com> <877f9dd4kp.fsf@intel.com> <34ef3414-952d-461f-bc3c-a47fadd1b69a@samsung.com> <87k2d3qgmm.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87k2d3qgmm.fsf@intel.com> X-Operating-System: Linux phenom 4.6.0-1-amd64 User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3310 Lines: 87 On Thu, Oct 20, 2016 at 04:44:49PM +0300, Jani Nikula wrote: > On Thu, 20 Oct 2016, Andrzej Hajda wrote: > > Hi Jani, > > > > Forgive me late response. > > > > On 12.10.2016 16:28, Jani Nikula wrote: > >> On Wed, 12 Oct 2016, Emil Velikov wrote: > >>> On 11 October 2016 at 10:33, Jani Nikula wrote: > >>>> On Tue, 11 Oct 2016, "Sun, Jing A" wrote: > >>>>> It's needed that DRM Driver module could be removed and reloaded after > >>>>> kernel booting on the projects that I have been working on, and I hope > >>>>> such module type change could be accepted. Looks like Iwai has similar > >>>>> change request as well. Would you please review it and let us know if > >>>>> any concerns? > >>>> Looking at the Kconfig, selecting CONFIG_DRM_MIPI_DSI is against the > >>>> recommendations of Documentation/kbuild/kconfig-language.txt: > >>>> > >>>> select should be used with care. select will force > >>>> a symbol to a value without visiting the dependencies. > >>>> By abusing select you are able to select a symbol FOO even > >>>> if FOO depends on BAR that is not set. > >>>> In general use select only for non-visible symbols > >>>> (no prompts anywhere) and for symbols with no dependencies. > >>>> That will limit the usefulness but on the other hand avoid > >>>> the illegal configurations all over. > >>>> > >>>> Indeed, you may end up with CONFIG_DRM_MIPI_DSI=y and CONFIG_DRM=m, > >>>> which violates DRM_MIPI_DSI dependency on CONFIG_DRM. This is broken and > >>>> should be fixed. The suggested patch does *not* fix this issue. > >>>> > >>> Jani, git log suggests you as the unfortunate author of the select > >>> DRM_MIPI_DSI/select DRM_PANEL hunks in i915 ;-) > >> /o\ > >> > >> As much as my present self would like to scold my past self for all his > >> mistakes, I have to remind myself that it is the mistakes that have > >> given me invaluable experience that my past self didn't have. I can only > >> hope my future self will have time to fix even a fraction of the > >> mistakes. > >> > >> Anyway, as Andrzej pointed out, all configs that select DRM_MIPI_DSI > >> also depend on DRM, so this problem can't currently occur. Once dsi bus > >> un-registration gets addressed, we can turn DRM_MIPI_DSI into a tristate > >> config (i.e. a loadable module). > > > > There is already patch adding bus unregistration [1]. It was published > > together > > with 'tristate' patch [2], both were created by Takashi few months ago. > > Right. So make that "Once dis bus un-registration gets merged > upstream". ;) Someone volunteering for some review pls? -Daniel > > BR, > Jani. > > > > > > [1]: > > https://lists.freedesktop.org/archives/dri-devel/2016-August/114870.html > > [2]: > > https://lists.freedesktop.org/archives/dri-devel/2016-August/114497.html > > > > Regards > > Andrzej > > > >> > >> BR, > >> Jani. > >> > > > > -- > Jani Nikula, Intel Open Source Technology Center > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch