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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 40055C388F7 for ; Tue, 3 Nov 2020 10:31:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBFD420756 for ; Tue, 3 Nov 2020 10:31:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="cJmsOmPV"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="k7tiSTzp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727530AbgKCKbU (ORCPT ); Tue, 3 Nov 2020 05:31:20 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:37172 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727443AbgKCKbT (ORCPT ); Tue, 3 Nov 2020 05:31:19 -0500 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1604399477; 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=4YPfyThdfqh+Ek0aAZOjucScX+kZFKAkhTa4zTnlBMU=; b=cJmsOmPV8GxzrObsOJzXJvTYMLL9xzFykDdEjxeqVusW8aVOVPJKjwbe7RH/Qi4KGazgb6 EXRzP0xXM42TRoQIjBOjqlb6E6IJNMg5Uj8mAc5cqfbHJfnhvPpar3uOMOKW8ezN121T8a SZhNsRibqapisx5f/5weainDJpjip7on3mdg+F9fcAxJ8oPkKlaYWreRU8WbB5JD6pr4qJ F07XA3El6TMzHtEVCrcFtl5Mfsj+eyD8kEiVd6Zd3AuGeEJN8dVA/THmr8KCllF2pe5+Dw I2o5pQOvke7qTwY4QNIw/OC1C03cMdbGZqpZ5ly8lJw41X8M2mgMCZ2GC3DoNA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1604399477; 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=4YPfyThdfqh+Ek0aAZOjucScX+kZFKAkhTa4zTnlBMU=; b=k7tiSTzpqGHQ8uDde18bylPddN7ucdzaebd1+q9xcVIWj2XjHe6Ebn2vilYBp7//HFtXyS 9Q9mwA+dO8xE2cDA== To: Marc Zyngier Cc: Frank Wunderlich , Ryder Lee , linux-mediatek@lists.infradead.org, Frank Wunderlich , linux-kernel@vger.kernel.org, Matthias Brugger , linux-pci@vger.kernel.org, Bjorn Helgaas Subject: Re: Aw: Re: [PATCH] pci: mediatek: fix warning in msi.h In-Reply-To: <901c5eb8bbaa3fe53ddc8f65917e48ef@kernel.org> References: <20201031140330.83768-1-linux@fw-web.de> <878sbm9icl.fsf@nanos.tec.linutronix.de> <87lfflti8q.wl-maz@kernel.org> <1604253261.22363.0.camel@mtkswgap22> <87k0v4u4uq.wl-maz@kernel.org> <87pn4w90hm.fsf@nanos.tec.linutronix.de> <87h7q791j8.fsf@nanos.tec.linutronix.de> <877dr38kt8.fsf@nanos.tec.linutronix.de> <901c5eb8bbaa3fe53ddc8f65917e48ef@kernel.org> Date: Tue, 03 Nov 2020 11:31:17 +0100 Message-ID: <87k0v27mve.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Nov 03 2020 at 09:54, Marc Zyngier wrote: > On 2020-11-02 22:18, Thomas Gleixner wrote: >> So we really need some other solution and removing the warning is not >> an option. If MSI is enabled then we want to get a warning when a PCI >> device has no MSI domain associated. Explicitly expressing the PCIE >> brigde misfeature of not supporting MSI is way better than silently >> returning an error code which is swallowed anyway. > > I don't disagree here, though the PCI_MSI_ARCH_FALLBACKS mechanism > makes it more difficult to establish. Only for the few leftovers which implement msi_controller, i.e. drivers/pci/controller/pci-hyperv.c drivers/pci/controller/pci-tegra.c drivers/pci/controller/pcie-rcar-host.c drivers/pci/controller/pcie-xilinx.c The architectures which select PCI_MSI_ARCH_FALLBACKS are: arch/ia64/Kconfig: select PCI_MSI_ARCH_FALLBACKS if PCI_MSI arch/mips/Kconfig: select PCI_MSI_ARCH_FALLBACKS if PCI_MSI arch/powerpc/Kconfig: select PCI_MSI_ARCH_FALLBACKS if PCI_MSI arch/s390/Kconfig: select PCI_MSI_ARCH_FALLBACKS if PCI_MSI arch/sparc/Kconfig: select PCI_MSI_ARCH_FALLBACKS if PCI_MSI implement arch_setup_msi_irq() which makes it magically work :) >> Whatever the preferred way is via flags at host probe time or flagging >> it post probe I don't care much as long as it is consistent. > > Host probe time is going to require some changes in the core PCI api, > as everything that checks for a MSI domain is based on the pci_bus > structure, which is only allocated much later. Yeah, it's nasty. One possible solution is to add flags or a callback to pci_ops, but it's not pretty either. I think we should go with the 'mark it after pci_host_probe()' hack for 5.10-rc. The real fix will be larger and go into 5.11. Thoughts? Thanks, tglx