From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCH] drm/exynos: Fix build breakage on !DRM_EXYNOS_FIMD Date: Mon, 04 May 2015 21:43:25 +0900 Message-ID: <5547696D.8000300@gmail.com> References: <1430539706-2945-1-git-send-email-k.kozlowski.k@gmail.com> <55472339.8040408@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-pd0-f171.google.com ([209.85.192.171]:33085 "EHLO mail-pd0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752616AbbEDMnc (ORCPT ); Mon, 4 May 2015 08:43:32 -0400 In-Reply-To: Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Daniel Stone Cc: Inki Dae , linux-samsung-soc , Seung-Woo Kim , Linux Kernel Mailing List , dri-devel , Kyungmin Park , Kukjin Kim , "linux-arm-kernel@lists.infradead.org" 2015-05-04 20:34 GMT+09:00 Daniel Stone : > Hi, > > On 4 May 2015 at 08:43, Inki Dae wrote: >> On 2015=EB=85=84 05=EC=9B=94 02=EC=9D=BC 13:08, Krzysztof Kozlowski = wrote: >>> Selecting CONFIG_FB_S3C disables CONFIG_DRM_EXYNOS_FIMD leading to = build >>> error: >> >> No, eDP has no any dependency of FIMD but DECON. Just add dependency >> code like below, >> >> config DRM_EXYNOS7_DECON >> bool "Exynos DRM DECON" >> - depends on DRM_EXYNOS >> + depends on DRM_EXYNOS && !FB_S3C Actually my commit message was not detailed enough. The FB_S3C here won't solve the issue because you may: 1, disable FIMD and FB_S3C, 2, enabke DECON and DP, and it won't compile. Currently the FIMD must be enabled if DRM_EXYNOS_DP is enabled. > > But it does clearly and explicitly call fimd_dp_clock_enable from > exynos_dp_powero{n,ff}. So the dependency you're proposing seems > backwards: it's not an expression of the requirements of the current > code (that FIMD DP code be available, i.e. CONFIG_DRM_EXYNOS_FIMD is > selected), but an indirect expression of another dependency > (CONFIG_FB_S3C disables CONFIG_DRM_EXYNOS_FIMD, so disable > CONFIG_FB_S3C). > > Additionally, as the call comes from exynos_dp_core.c, which is built > by CONFIG_DRM_EXYNOS_DP (an explicitly user-selectable option), why > shouldn't the dependency be there? Ah, because the dependency on DP i= s > for (DECON || FIMD), but as DECON doesn't provide > fimd_dp_clock_enable(), it doesn't seem like it would compile if you > selected DECON and not FIMD. > > So, for me, the cleanest solution would be config DRM_EXYNOS_DP gains > a hard dependency on DRM_EXYNOS_FIMD, at least until it can be fixed > to compile without FIMD. Right, you correctly pointed current dependencies. Still it looks littl= e hacky because EXYNOS_DP may work with FIMD or DECON. It does not really need FIMD. Using ifdefs in headers is not uncommon - many core subsystems do this that way to provide stubs. Probably the cleanest way would be to provide by FIMD and DECON a commo= n interface for DP for such operation, something like: struct exynos_drm_crtc { struct drm_crtc base; ... void (*clock_enable)(struct exynos_drm_crtc *crtc, bool enable) ); which, if non-NULL, will be called by exynos_dp_core.c: static void exynos_dp_poweron(struct exynos_dp_device *dp) { ... if (crtc->clock_enable) crtc->clock_enable(crtc, true); } What do you think? Best regards, Krzysztof