From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753796AbeEaEyh (ORCPT ); Thu, 31 May 2018 00:54:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:58074 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751381AbeEaEyf (ORCPT ); Thu, 31 May 2018 00:54:35 -0400 Date: Wed, 30 May 2018 23:54:34 -0500 From: Bjorn Helgaas To: Lukas Wunner Cc: linux-pci@vger.kernel.org, Oza Pawandeep , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 1/2] PCI/AER: Decode Error Source Requester ID Message-ID: <20180531045434.GS39853@bhelgaas-glaptop.roam.corp.google.com> References: <152770259826.80701.7360032106128917833.stgit@bhelgaas-glaptop.roam.corp.google.com> <152770285586.80701.6545710900591672975.stgit@bhelgaas-glaptop.roam.corp.google.com> <20180530183241.GA20222@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180530183241.GA20222@wunner.de> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 30, 2018 at 08:32:41PM +0200, Lukas Wunner wrote: > On Wed, May 30, 2018 at 12:54:15PM -0500, Bjorn Helgaas wrote: > > void aer_print_port_info(struct pci_dev *dev, struct aer_err_info *info) > > { > > - pci_info(dev, "AER: %s%s error received: id=%04x\n", > > + u8 bus = info->id >> 8; > > + u8 devfn = info->id & 0xff; > > + > > + pci_info(dev, "AER: %s%s error received: %04x:%02x:%02x.%d\n", > > info->multi_error_valid ? "Multiple " : "", > > - aer_error_severity_string[info->severity], info->id); > > + aer_error_severity_string[info->severity], > > + pci_domain_nr(dev->bus), bus, devfn >> 3, devfn & 0x7); > > I think PCI_SLOT(devfn), PCI_FUNC(devfn) is a bit more readable. I used those originally, but of course those definitions predate PCIe so they aren't clearly related to a Requester ID. I searched the PCIe spec for the specifics of the Requester ID composition. It was surprisingly hard to find a clear statement. The best I found was PCIe r4.0, sec 6.13, which says Routing IDs, Requester IDs, and Completer IDs are 16-bit identifiers traditionally composed of three fields: an 8-bit Bus Number, a 5-bit Device Number, and a 3-bit Function Number. Even that isn't specific about where the fields are, But it's probably not worth obsessing over this and PCI_SLOT() and PCI_FUNC() are definitely more readable, so I changed them.