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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 0D4BBC433FE for ; Mon, 7 Dec 2020 03:14:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0D7C22D06 for ; Mon, 7 Dec 2020 03:14:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727393AbgLGDOg (ORCPT ); Sun, 6 Dec 2020 22:14:36 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44350 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726484AbgLGDOg (ORCPT ); Sun, 6 Dec 2020 22:14:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607310789; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Tyqx0n2wiRk01BnAx7gZU3drnJqHx5Dd1+WachDCKXM=; b=FFKMUf46bA5KMP3QJVFknrz1Qc9LdyQQog8OfY91fFfhGV/MAazpGBS3CwtC3b+s90eZE6 sCnwgvMf6bz5ux8yYPzUxqEPoO1E2saTrbXYdB3SzdSmUmvSxVCnN0xmLIpXvkQmWHR12U p7HEKU5FqKoV+ruom7E0CfbBUEKfwb0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-247-RAZE5x0oNVqj6l6BR1IHaQ-1; Sun, 06 Dec 2020 22:13:05 -0500 X-MC-Unique: RAZE5x0oNVqj6l6BR1IHaQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 316AB858183; Mon, 7 Dec 2020 03:13:03 +0000 (UTC) Received: from [10.72.13.171] (ovpn-13-171.pek2.redhat.com [10.72.13.171]) by smtp.corp.redhat.com (Postfix) with ESMTP id B38E91002382; Mon, 7 Dec 2020 03:12:51 +0000 (UTC) Subject: Re: [PATCH v2 2/2] drivers: gpio: add virtio-gpio guest driver To: "Michael S. Tsirkin" , "Enrico Weigelt, metux IT consult" Cc: "Enrico Weigelt, metux IT consult" , linux-kernel@vger.kernel.org, corbet@lwn.net, linus.walleij@linaro.org, bgolaszewski@baylibre.com, linux-doc@vger.kernel.org, linux-gpio@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-riscv@lists.infradead.org, stefanha@redhat.com, msuchanek@suse.de References: <20201203191135.21576-1-info@metux.net> <20201203191135.21576-2-info@metux.net> <8209ce55-a4aa-f256-b9b9-f7eb3cac877b@redhat.com> <96aca1e6-2d5a-deb1-2444-88f938c7a9de@metux.net> <20201205142218-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <842519cc-94ca-3c11-ddd6-543e5a89c998@redhat.com> Date: Mon, 7 Dec 2020 11:12:50 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201205142218-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 2020/12/6 上午3:32, Michael S. Tsirkin wrote: > On Sat, Dec 05, 2020 at 08:59:55AM +0100, Enrico Weigelt, metux IT consult wrote: >> On 04.12.20 04:35, Jason Wang wrote: >> >>>> --- a/drivers/gpio/Kconfig >>>> +++ b/drivers/gpio/Kconfig >>>> @@ -1615,6 +1615,15 @@ config GPIO_MOCKUP >>>>         tools/testing/selftests/gpio/gpio-mockup.sh. Reference the >>>> usage in >>>>         it. >>>>   +config GPIO_VIRTIO >>>> +    tristate "VirtIO GPIO support" >>>> +    depends on VIRTIO >>> >>> Let's use select, since there's no prompt for VIRTIO and it doesn't have >>> any dependencies. >> whoops, it's not that simple: >> >> make: Entering directory '/home/nekrad/src/apu2-dev/pkg/kernel.apu2.git' >> make[1]: Entering directory >> '/home/nekrad/src/dk/DistroKit/platform-x86_64/build-target/linux-5.8.9-build' >> GEN Makefile >> drivers/gpu/drm/Kconfig:74:error: recursive dependency detected! >> drivers/gpu/drm/Kconfig:74: symbol DRM_KMS_HELPER is selected by >> DRM_VIRTIO_GPU >> drivers/gpu/drm/virtio/Kconfig:2: symbol DRM_VIRTIO_GPU depends on VIRTIO >> drivers/virtio/Kconfig:2: symbol VIRTIO is selected by GPIO_VIRTIO >> drivers/gpio/Kconfig:1618: symbol GPIO_VIRTIO depends on GPIOLIB >> drivers/gpio/Kconfig:14: symbol GPIOLIB is selected by I2C_MUX_LTC4306 >> drivers/i2c/muxes/Kconfig:47: symbol I2C_MUX_LTC4306 depends on I2C >> drivers/i2c/Kconfig:8: symbol I2C is selected by FB_DDC >> drivers/video/fbdev/Kconfig:63: symbol FB_DDC depends on FB >> 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 >> >> Seems that we can only depend on or select some symbol - we run into >> huge trouble if thats mixed. Just changed DRM_VIRTIO_GPU to just select >> VIRIO instead of depending on it, and now it works. >> >> I've posted another patch for fixing drivers/gpu/drm/virtio/Kconfig >> to use 'select' instead of 'depends on'. > It seems a bit of a mess, at this point I'm not entirely sure when > should drivers select VIRTIO and when depend on it. > > The text near it says: > > # SPDX-License-Identifier: GPL-2.0-only > config VIRTIO > tristate > help > This option is selected by any driver which implements the virtio > bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG > or CONFIG_S390_GUEST. > > Which seems clear enough and would indicate drivers for devices *behind* > the bus should not select VIRTIO and thus presumably should "depend on" it. > This is violated in virtio console and virtio fs drivers. > > For console it says: > > commit 9f30eb29c514589e16f2999ea070598583d1f6ec > Author: Michal Suchanek > Date: Mon Aug 31 18:58:50 2020 +0200 > > char: virtio: Select VIRTIO from VIRTIO_CONSOLE. > > Make it possible to have virtio console built-in when > other virtio drivers are modular. > > Signed-off-by: Michal Suchanek > Reviewed-by: Amit Shah > Link: https://lore.kernel.org/r/20200831165850.26163-1-msuchanek@suse.de > Signed-off-by: Greg Kroah-Hartman > > which seems kind of bogus - why do we care about allowing a builtin > virtio console driver if the pci virtio bus driver is a module? > There won't be any devices on the bus to attach to ... For testing like switching bus from pci to MMIO? > And for virtio fs it was like this from the beginning. > > I am inclined to fix console and virtio fs to depend on VIRTIO: > select is harder to use correctly ... > > Jason? I think it works, but we need a prompt for VIRTIO otherwise there's no way to enable it. Thanks > > >> -- >> --- >> Hinweis: unverschlüsselte E-Mails können leicht abgehört und manipuliert >> werden ! Für eine vertrauliche Kommunikation senden Sie bitte ihren >> GPG/PGP-Schlüssel zu. >> --- >> Enrico Weigelt, metux IT consult >> Free software and Linux embedded engineering >> info@metux.net -- +49-151-27565287