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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 D30A6C4707F for ; Thu, 27 May 2021 22:13:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B589260FE9 for ; Thu, 27 May 2021 22:13:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236024AbhE0WPA (ORCPT ); Thu, 27 May 2021 18:15:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:58342 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233563AbhE0WO4 (ORCPT ); Thu, 27 May 2021 18:14:56 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B229C60FE9; Thu, 27 May 2021 22:13:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622153603; bh=0VCssnCyaXoacCezAXEXIMcwiumMm+CUza0JXKuGcn0=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=Ysiv4Ec97svTCtG94GRkIO1KBpUvRC9HT80WQVcQbk7l4bOuYYIPgo+ExOo4bm5cs eHp0U8P9PCeA6nP2KxC0Her5gt3x4TKWwuJnGRFs3PJrsnupjS6Esac6AHn7iyvdb7 vkexzd0xzKfFlhiQ4tgaYyIDqdqbFNlrlr59IQemXRfFfPKKZxjBHJn4hPnjXU3bEW ik5drL17rXZT8waJaUZKGUQ5wYstN+ZJk7kQckLGtbJV/jH+UGaaJj1hK9sughjiOv GviyOAU/TUB8m6iMopa67DNEHOS8G1QMTDzgDpO3y8m8KdXG1LFfghFAcN6vkdGnGG blJ8ucwp9fp+Q== Date: Thu, 27 May 2021 17:13:19 -0500 From: Bjorn Helgaas To: Kai-Heng Feng Cc: bhelgaas@google.com, "open list:PCI SUBSYSTEM" , open list Subject: Re: [PATCH v2] PCI: Coalesce contiguous regions for host bridges Message-ID: <20210527221319.GA1435795@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210401131252.531935-1-kai.heng.feng@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 01, 2021 at 09:12:52PM +0800, Kai-Heng Feng wrote: > Built-in graphics on HP EliteDesk 805 G6 doesn't work because graphics > can't get the BAR it needs: > [ 0.611504] pci_bus 0000:00: root bus resource [mem 0x10020200000-0x100303fffff window] > [ 0.611505] pci_bus 0000:00: root bus resource [mem 0x10030400000-0x100401fffff window] > ... > [ 0.638083] pci 0000:00:08.1: bridge window [mem 0xd2000000-0xd23fffff] > [ 0.638086] pci 0000:00:08.1: bridge window [mem 0x10030000000-0x100401fffff 64bit pref] > [ 0.962086] pci 0000:00:08.1: can't claim BAR 15 [mem 0x10030000000-0x100401fffff 64bit pref]: no compatible bridge window > [ 0.962086] pci 0000:00:08.1: [mem 0x10030000000-0x100401fffff 64bit pref] clipped to [mem 0x10030000000-0x100303fffff 64bit pref] > [ 0.962086] pci 0000:00:08.1: bridge window [mem 0x10030000000-0x100303fffff 64bit pref] > [ 0.962086] pci 0000:07:00.0: can't claim BAR 0 [mem 0x10030000000-0x1003fffffff 64bit pref]: no compatible bridge window > [ 0.962086] pci 0000:07:00.0: can't claim BAR 2 [mem 0x10040000000-0x100401fffff 64bit pref]: no compatible bridge window > > However, the root bus has two contiguous regions that can contain the > child resource requested. > > Bjorn Helgaas pointed out that we can simply coalesce contiguous regions > for host bridges, since host bridge don't have _SRS. So do that > accordingly to make child resource can be contained. This change makes > the graphics works on the system in question. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212013 > Suggested-by: Bjorn Helgaas > Signed-off-by: Kai-Heng Feng Applied to pci/resource for v5.14 with subject: PCI: Coalesce host bridge contiguous apertures Thanks! > --- > v2: > - Coalesce all contiguous regresion in pci_register_host_bridge(), if > conditions are met. > > drivers/pci/probe.c | 49 +++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 45 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 953f15abc850..3607ce7402b4 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -19,6 +19,7 @@ > #include > #include > #include > +#include > #include "pci.h" > > #define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */ > @@ -874,14 +875,30 @@ static void pci_set_bus_msi_domain(struct pci_bus *bus) > dev_set_msi_domain(&bus->dev, d); > } > > +static int res_cmp(void *priv, struct list_head *a, struct list_head *b) > +{ > + struct resource_entry *entry1, *entry2; > + > + entry1 = container_of(a, struct resource_entry, node); > + entry2 = container_of(b, struct resource_entry, node); > + > + if (entry1->res->flags != entry2->res->flags) > + return entry1->res->flags > entry2->res->flags; > + > + if (entry1->offset != entry2->offset) > + return entry1->offset > entry2->offset; > + > + return entry1->res->start > entry2->res->start; > +} > + > static int pci_register_host_bridge(struct pci_host_bridge *bridge) > { > struct device *parent = bridge->dev.parent; > - struct resource_entry *window, *n; > + struct resource_entry *window, *next, *n; > struct pci_bus *bus, *b; > - resource_size_t offset; > + resource_size_t offset, next_offset; > LIST_HEAD(resources); > - struct resource *res; > + struct resource *res, *next_res; > char addr[64], *fmt; > const char *name; > int err; > @@ -959,11 +976,35 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) > if (nr_node_ids > 1 && pcibus_to_node(bus) == NUMA_NO_NODE) > dev_warn(&bus->dev, "Unknown NUMA node; performance will be reduced\n"); > > + /* Sort and coalesce contiguous windows */ > + list_sort(NULL, &resources, res_cmp); > + resource_list_for_each_entry_safe(window, n, &resources) { > + if (list_is_last(&window->node, &resources)) > + break; > + > + next = list_next_entry(window, node); > + offset = window->offset; > + res = window->res; > + next_offset = next->offset; > + next_res = next->res; > + > + if (res->flags != next_res->flags || offset != next_offset) > + continue; > + > + if (res->end + 1 == next_res->start) { > + next_res->start = res->start; > + res->flags = res->start = res->end = 0; > + } > + } > + > /* Add initial resources to the bus */ > resource_list_for_each_entry_safe(window, n, &resources) { > - list_move_tail(&window->node, &bridge->windows); > offset = window->offset; > res = window->res; > + if (!res->end) > + continue; > + > + list_move_tail(&window->node, &bridge->windows); > > if (res->flags & IORESOURCE_BUS) > pci_bus_insert_busn_res(bus, bus->number, res->end); > -- > 2.30.2 >