From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by smtp.lore.kernel.org (Postfix) with ESMTP id B877CC77B75
	for <linux-kernel@archiver.kernel.org>; Wed,  3 May 2023 07:20:14 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S229710AbjECHUN (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Wed, 3 May 2023 03:20:13 -0400
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33852 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S229511AbjECHUJ (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 3 May 2023 03:20:09 -0400
Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD28040F1
        for <linux-kernel@vger.kernel.org>; Wed,  3 May 2023 00:19:27 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;
        s=mimecast20190719; t=1683098366;
        h=from:from:reply-to:subject:subject:date:date:message-id:message-id:
         to:to:cc:cc:mime-version:mime-version:content-type:content-type:
         in-reply-to:in-reply-to:references:references;
        bh=JWuwBsoA7E+ixFPnuQyU62/zGQyUSXimh/xtxQzzOds=;
        b=Yih/rFJAHiaY8DcTzymU86MuRim2k6zUA0W3Eysk7pU/42d2CSiANyDtU2oEPKsW0GHeeu
        9yQVvzZO/+sXgBHFGSwqBiTV/l9uzH8CfUb6mbArG+Vng9CT49t7qBA973Gp2SvERKGl7X
        Q+knl9oug8drqKei940PcigipRUFEgU=
Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com
 [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS
 (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id
 us-mta-22-ecsSxssXPAOomcQrcDML8A-1; Wed, 03 May 2023 03:19:24 -0400
X-MC-Unique: ecsSxssXPAOomcQrcDML8A-1
Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-3f18c2b2110so14861735e9.3
        for <linux-kernel@vger.kernel.org>; Wed, 03 May 2023 00:19:24 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20221208; t=1683098363; x=1685690363;
        h=mime-version:message-id:date:references:in-reply-to:subject:cc:to
         :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to;
        bh=JWuwBsoA7E+ixFPnuQyU62/zGQyUSXimh/xtxQzzOds=;
        b=aG8KaTsN0MPZDha+8pivdEwAdsY61gZeDga0Vvxx21qtCLuZIcs2OcOuJPBmtZxWWE
         meIPb/JHeg1qIfnr5PnDP1Fop8vmUGGdK5gbkRiE5RHU2Er7Bd5n86gWEtXHX69GRcDN
         xNE11pjL54zO0nQjTkPe7q6SBUQDnlx8NAoDBEqe+5jfRzkWItq31Yj1Ka//5FnXX6ou
         wC0BAFSyvg8ypZtzeuduqdji/GJeS0OkT19GaR9R1aGNoRBgi67Th1tNkho4IEvNlfFN
         ZSpzrNOBFXYFB+jBWn4FGlEP/+8U3V4Okp1CpBXL0TEQeb6iYyeKWcBP7Kxz7UcIjFKl
         VYsA==
X-Gm-Message-State: AC+VfDzHNtG5X764QBwefhSj87Mn/Ue/IOxxnUJuiimCTl3KLlGNGaqI
        tUc8ggMqhONG910h1JpZ0wHHasJLBYMAAa/RO3njtc1CMF77AB1H0jO1f6OHHllVgTsnnu7ZsSI
        lH2AK1o56ipZ7iWVuscLAR4CB
X-Received: by 2002:a5d:4536:0:b0:2f9:4fe9:74de with SMTP id j22-20020a5d4536000000b002f94fe974demr14583284wra.16.1683098363276;
        Wed, 03 May 2023 00:19:23 -0700 (PDT)
X-Google-Smtp-Source: ACHHUZ4YmDJ5fSjEX9bYJcvGxxrKGNEefuG/olEhGMwhxvTP6ZpCZhJEgcZLb8yFcLBX87Q12Wuhlg==
X-Received: by 2002:a5d:4536:0:b0:2f9:4fe9:74de with SMTP id j22-20020a5d4536000000b002f94fe974demr14583271wra.16.1683098363001;
        Wed, 03 May 2023 00:19:23 -0700 (PDT)
Received: from localhost (205.pool92-176-231.dynamic.orange.es. [92.176.231.205])
        by smtp.gmail.com with ESMTPSA id u7-20020a5d5147000000b002cde25fba30sm33050954wrt.1.2023.05.03.00.19.22
        (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
        Wed, 03 May 2023 00:19:22 -0700 (PDT)
From:   Javier Martinez Canillas <javierm@redhat.com>
To:     Thomas Zimmermann <tzimmermann@suse.de>,
        Sam Ravnborg <sam@ravnborg.org>
Cc:     linux-arch@vger.kernel.org, linux-fbdev@vger.kernel.org,
        linux-ia64@vger.kernel.org, loongarch@lists.linux.dev,
        arnd@arndb.de, deller@gmx.de, chenhuacai@kernel.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        James.Bottomley@hansenpartnership.com,
        linux-m68k@lists.linux-m68k.org, geert@linux-m68k.org,
        linux-parisc@vger.kernel.org, vgupta@kernel.org,
        sparclinux@vger.kernel.org, kernel@xen0n.name,
        linux-snps-arc@lists.infradead.org, davem@davemloft.net,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 4/6] fbdev: Include <linux/io.h> via <asm/fb.h>
In-Reply-To: <563673c0-799d-e353-974c-91b1ab881a22@suse.de>
References: <20230502130223.14719-1-tzimmermann@suse.de>
 <20230502130223.14719-5-tzimmermann@suse.de>
 <20230502195429.GA319489@ravnborg.org>
 <563673c0-799d-e353-974c-91b1ab881a22@suse.de>
Date:   Wed, 03 May 2023 09:19:21 +0200
Message-ID: <87354dyj9i.fsf@minerva.mail-host-address-is-not-set>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Thomas Zimmermann <tzimmermann@suse.de> writes:

Hello Thomas,

> Am 02.05.23 um 21:54 schrieb Sam Ravnborg:
>> On Tue, May 02, 2023 at 03:02:21PM +0200, Thomas Zimmermann wrote:

[...]

>>>   #include <linux/console.h> /* Why should fb driver call console functions? because console_lock() */
>>>   #include <video/vga.h>
>>>   
>>> +#include <asm/fb.h>
>> 
>> When we have a header like linux/fb.h - it is my understanding that it is
>> preferred to include that file, and not the asm/fb.h variant.
>> 
>> This is assuming the linux/fb.h contains the generic stuff, and includes
>> asm/fb.h for the architecture specific parts.
>> 
>> So drivers will include linux/fb.h and then they automatically get the
>> architecture specific parts from asm/fb.h.
>> 
>> In other words, drivers are not supposed to include asm/fb.h, if
>> linux.fb.h exists - and linux/fb.h shall include the asm/fb.h.
>> 
>> If the above holds true, then it is wrong and not needed to add asm/fb.h
>> as seen above.
>> 
>> 
>> There are countless examples where the above are not followed,
>> but to my best understanding the above it the preferred way to do it.
>
> Where did youher this? I only know about this in the case of asm/io.h 
> vs. linux/io.h.
>

I understand that's the case too. I believe even checkpatch.pl complains
about it? (not that the script always get right, but just as an example).

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat