From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751973AbdHCJ4A (ORCPT ); Thu, 3 Aug 2017 05:56:00 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:37434 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751229AbdHCJzz (ORCPT ); Thu, 3 Aug 2017 05:55:55 -0400 Subject: Re: [PATCH v2] PCI/MSI: Improve MSI alias detection To: Robin Murphy , helgaas@kernel.org References: <63f5b8eef3c6d903bf97ca7fea0daa2e832be02f.1501610322.git.robin.murphy@arm.com> Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, david.daney@cavium.com, alex.williamson@redhat.com From: Marc Zyngier Organization: ARM Ltd Message-ID: Date: Thu, 3 Aug 2017 10:55:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <63f5b8eef3c6d903bf97ca7fea0daa2e832be02f.1501610322.git.robin.murphy@arm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/08/17 18:59, Robin Murphy wrote: > Currently, we handle all DMA aliases equally when calculating MSI > requester IDs for the generic infrastructure. This turns out to be the > wrong thing to do in the face of pure DMA quirks like those of Marvell > SATA cards, where in the usual case the last thing seen in the alias > walk is the DMA phantom function: we end up configuring the MSI > doorbell to expect that alias, then find we have no interrupts since > the MSI writes still come from the 'real' RID, thus get filtered out > and ignored. > > Improve the alias walk to only account for the topological aliases that > matter, based on the logic from the Intel IRQ remapping code. > > Signed-off-by: Robin Murphy Acked-by: Marc Zyngier M. -- Jazz is not dead. It just smells funny...