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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 81427C07E9B for ; Wed, 21 Jul 2021 05:58:18 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B95B360725 for ; Wed, 21 Jul 2021 05:58:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B95B360725 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=BYfDSkBYBfHXIf7iOPQhLvQBrBhRdhZXFeQ11mZ3OzI=; b=CGI0xrKMDv9lA/ cU8/Evcxujqj+2T6SGc0Xzxa2oJzwlTr6SKAIeVLurGaxsMznFtfiNmR/lr0EdskIgjS2OD/036re qJ+BGp3Q3Y6CF3wjtBBwsEhvwWX5kGOKKQPFqtUvpjE4Q2+w2mXurPmvHmtDH1KGOeTGEoJkV+vgr pCW4RqKeYJHzCVSrdUiMu72y1jJLPDJaTyjEWUNkH3OSB0gAPwW+z0kpe3OfguQFT3VomfH2o1qTP uKoO+9yxXu1heAI+NnIr2atleF4zjqCrGjJ0gyVoqQ1nF/2bS3Fea84zadnG0Y1fu7N41PDEgplmY ELUAvtiSGnWATi/MjRGg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m65F3-00EXgP-Mb; Wed, 21 Jul 2021 05:58:01 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m65F2-00EXgC-92 for linux-riscv@bombadil.infradead.org; Wed, 21 Jul 2021 05:58:00 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=VjxcWlaf6z0Lp4+alJYi2EBaYHfLu4QPezFerPqHPUU=; b=L0uDkpXz+IDMULUL75c929bkUv meFKGb8M7Wf0LHsf66mktNzJ5FocDZywLQXFXBZOMJo9VYoZ8Emq2mwiSqlboutnWEQk7OctqytT1 W+rz7Helu5Ynob2CqWJZBB64lhO+LLnZZsS6sEY/mvnFcOGH5icTyPVNl6HjOu7Ty5eoBugcGgsiR gTz1kS5JFu4FodM+Y+LwfXvR8lxXS85uK4m4bBEdBHXIdDoACFXcV4IL3y9UbhTU5QPvwxTHyi2eQ MDSqIhwmBO1Zml8msAuz1lSq6tRW6SYD+dquP4++xj89Mos71CVGti/ZJn4JfKvqlyIW/qNfP8wZ4 2HTwbhUQ==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m65Es-008qtW-G2; Wed, 21 Jul 2021 05:57:51 +0000 Date: Wed, 21 Jul 2021 06:57:50 +0100 From: Christoph Hellwig To: Vincent Chen Cc: linux-riscv@lists.infradead.org, palmer@dabbelt.com Subject: Re: [PATCH v2] riscv: Kconfig: do not select PCI_MSI if CONIFG_PCI is enabled Message-ID: References: <1626838752-7013-1-git-send-email-vincent.chen@sifive.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1626838752-7013-1-git-send-email-vincent.chen@sifive.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Wed, Jul 21, 2021 at 11:39:12AM +0800, Vincent Chen wrote: > The CONFIG_PCI_MSI is used to allow device drivers to enable MSI. The MSI > enables a device to generate an interrupt using an inbound Memory Write > on its PCI bus instead of asserting a device IRQ pin. The whole mechanism > needs support from the PCI controller or generic interrupt controller and > the corresponding software driver. > > The RISC-V Kconfig file actively selects the PCI_MSI if users enable > CONFIG_PCI. However, the RISC-V specification does not require every RISC-V > platform shall have MSI support. In other words, Kconfig enables CONFIG_PCI > to allow PCI devices to use MSI, but due to lack of MSI support, the kernel > may not have any function to deal with the MSI from PCI devices. When this > case happens, it leads to the following warning message displayed in > booting a v5.10~v5.12 kernel. So make sure the runtime detection works fine. An x86 kernel with CONFIG_PCI_MSI also works on non-MSI systems. NAK to this patch. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv