From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03A8DC388F9 for ; Sat, 31 Oct 2020 20:56:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0F07207DE for ; Sat, 31 Oct 2020 20:56:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727301AbgJaU4Y (ORCPT ); Sat, 31 Oct 2020 16:56:24 -0400 Received: from asavdk4.altibox.net ([109.247.116.15]:58924 "EHLO asavdk4.altibox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbgJaU4Y (ORCPT ); Sat, 31 Oct 2020 16:56:24 -0400 Received: from ravnborg.org (unknown [188.228.123.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by asavdk4.altibox.net (Postfix) with ESMTPS id D6C2080501; Sat, 31 Oct 2020 21:56:18 +0100 (CET) Date: Sat, 31 Oct 2020 21:56:17 +0100 From: Sam Ravnborg To: Lubomir Rintel Cc: Andrzej Hajda , Daniel Vetter , David Airlie , Rob Herring , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Rob Herring Subject: Re: [PATCH v6 2/2] drm/bridge: hx8837: add a Himax HX8837 display controller driver Message-ID: <20201031205617.GA1111106@ravnborg.org> References: <20201030030800.1036888-1-lkundrak@v3.sk> <20201030030800.1036888-3-lkundrak@v3.sk> <20201031080137.GB1044557@ravnborg.org> <20201031201259.GA294060@demiurge.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201031201259.GA294060@demiurge.local> X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=VafZwmh9 c=1 sm=1 tr=0 a=S6zTFyMACwkrwXSdXUNehg==:117 a=S6zTFyMACwkrwXSdXUNehg==:17 a=kj9zAlcOel0A:10 a=yQnS-YR962e6U0jWTX0A:9 a=CjuIK1q_8ugA:10 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lubomir. > > > > > + select BACKLIGHT_CLASS_DEVICE > > Please use a depends - using select on a symbol with a prompt is always > > wrong. Yeah, I know you then need to enable backlight to see this > > driver. Sorry, but this is the best we can do now. > > Many other drivers can cope with depends here. > > This results in a dependency loop: > > drivers/video/fbdev/Kconfig:12:error: recursive dependency detected! > drivers/video/fbdev/Kconfig:12: symbol FB is selected by DRM_KMS_FB_HELPER > drivers/gpu/drm/Kconfig:80: symbol DRM_KMS_FB_HELPER depends on DRM_KMS_HELPER > drivers/gpu/drm/Kconfig:74: symbol DRM_KMS_HELPER is selected by DRM_HIMAX_HX8837 > drivers/gpu/drm/bridge/Kconfig:51: symbol DRM_HIMAX_HX8837 depends on BACKLIGHT_CLASS_DEVICE > drivers/video/backlight/Kconfig:143: symbol BACKLIGHT_CLASS_DEVICE is selected by FB_BACKLIGHT > drivers/video/fbdev/Kconfig:187: symbol FB_BACKLIGHT depends on FB > > Unfortunately I have no idea how to resolve it at the moment. > > I suppose I can look further into it if necessary. Or is it okay if I > leave it at select BACKLIGHT_CLASS_DEVICE for now? Sigh, leave it as a select then :-( The "sigh" is not directed at you but the mess this BACKLIGHT_CLASS_DEVICE is and the limitations of Kconfig. Sam