From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f49.google.com ([74.125.83.49]:34326 "EHLO mail-pg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750710AbdEOVvM (ORCPT ); Mon, 15 May 2017 17:51:12 -0400 Received: by mail-pg0-f49.google.com with SMTP id u28so66221872pgn.1 for ; Mon, 15 May 2017 14:51:12 -0700 (PDT) Date: Mon, 15 May 2017 14:51:09 -0700 From: Brian Norris To: Alexander Duyck Cc: Bjorn Helgaas , "linux-pci@vger.kernel.org" , Alex Williamson , Jeffy Chen , Shawn Lin Subject: Re: [PATCH] pci: Disable master abort while waiting for an FLR to complete Message-ID: <20170515215109.GA100668@google.com> References: <20170512181107.13853.34680.stgit@localhost.localdomain> <20170515163623.GA15237@google.com> <20170515210033.GA58785@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170515210033.GA58785@google.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Mon, May 15, 2017 at 02:00:33PM -0700, Brian Norris wrote: > On Mon, May 15, 2017 at 12:48:30PM -0700, Alexander Duyck wrote: > > On Mon, May 15, 2017 at 9:36 AM, Brian Norris wrote: > > > So there may be several implementation bugs with RK3399. I don't know > > > how much can be fixed on Rockchip's side, vs. how much can be > > > accomodated in the PCI core. > > > > This is the kind of thing we have PCIe quirks for if nothing else. > > Odds are we should be able to work around it, it is just a matter of > > knowing what all the quirks are. > > Maybe your imagination for "quirks" isn't creative enough :) BTW, I meant to note that people have gone to some extreme lengths to handle buggy / quirky RCs. Look at drivers/pci/dwc/pci-imx6.c, which hooks all the way into the core ARM exception handling just to mask aborts! (See imx6q_pcie_abort_handler.) And they have some patches intended to fix crashes in 4.12-rc1 to hook synchronous aborts to return "all 1's". But that's extremely invasive and not very precise (I don't think that even checks the difference between PCI-induced aborts and other system aborts?). Probably not gonna fly on ARM64 either... Brian [1] [PATCH] PCI: imx6: fix downstream bus scanning https://patchwork.ozlabs.org/patch/760748/