From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:57242 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751458AbcFRSPu (ORCPT ); Sat, 18 Jun 2016 14:15:50 -0400 Date: Sat, 18 Jun 2016 13:15:46 -0500 From: Bjorn Helgaas To: "Yong, Jonathan" Cc: linux-pci@vger.kernel.org, bhelgaas@google.com Subject: Re: [PATCH v5] PCI: PTM preliminary implementation Message-ID: <20160618181546.GC20504@localhost> References: <1462956446-27361-1-git-send-email-jonathan.yong@intel.com> <1462956446-27361-2-git-send-email-jonathan.yong@intel.com> <20160613185648.GA6901@localhost> <575F5EAC.2030904@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <575F5EAC.2030904@intel.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Tue, Jun 14, 2016 at 09:32:28AM +0800, Yong, Jonathan wrote: > On 06/14/2016 02:56, Bjorn Helgaas wrote: > >I'm also a little confused about how Root Complex Integrated Endpoints > >are supposed to use PTM, since they don't have an upstream bridge. > >Maybe it has to do with an RCRB (Root Complex Register Block, spec > >r3.1, sec 7.2.3)? I don't think Linux really has any support for that > >(yet). > > The spec (7.32.3 PTM Control Register) says: > > For Root Complex Integrated Endpoints, system software must set this > field to the value reported in the Local Clock Granularity field by > the associated PTM Time Source. > > I'm not familiar with RC integrated endpoints either. I'm guessing > whatever device 0, function 0 on the "bus"? Just copy the > granularity value over? I don't know what the answer is, but I don't think device 0, function 0 is it. There's no reason to expect that to be related to an integrated endpoint. I suspect it has to do with the RCRB, but I haven't had a chance to work through that yet. For now, I just made it use zero (unknown) for the effective granularity of integrated endpoints. Bjorn