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PCI: Coalesce host bridge contiguous apertures

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Built-in graphics on HP EliteDesk 805 G6 doesn't work because graphics
can't get the BAR it needs:

  pci_bus 0000:00: root bus resource [mem 0x10020200000-0x100303fffff window]
  pci_bus 0000:00: root bus resource [mem 0x10030400000-0x100401fffff window]

  pci 0000:00:08.1:   bridge window [mem 0xd2000000-0xd23fffff]
  pci 0000:00:08.1:   bridge window [mem 0x10030000000-0x100401fffff 64bit pref]
  pci 0000:00:08.1: can't claim BAR 15 [mem 0x10030000000-0x100401fffff 64bit pref]: no compatible bridge window
  pci 0000:00:08.1: [mem 0x10030000000-0x100401fffff 64bit pref] clipped to [mem 0x10030000000-0x100303fffff 64bit pref]
  pci 0000:00:08.1:   bridge window [mem 0x10030000000-0x100303fffff 64bit pref]
  pci 0000:07:00.0: can't claim BAR 0 [mem 0x10030000000-0x1003fffffff 64bit pref]: no compatible bridge window
  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 apertures that can contain the
child resource requested.

Coalesce contiguous apertures so we can allocate from the entire contiguous
region.

[bhelgaas: fold in https://lore.kernel.org/r/20210528170242.1564038-1-kai.heng.feng@canonical.com]
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212013
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20210401131252.531935-1-kai.heng.feng@canonical.com
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Kai-Heng Feng 2021-04-01 21:12:52 +08:00 committed by Bjorn Helgaas
parent 6efb943b86
commit 65db04053e
1 changed files with 47 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
drivers/pci/probe.c
View File

@ -19,6 +19,7 @@
#include <linux/hypervisor.h>
#include <linux/irqdomain.h>
#include <linux/pm_runtime.h>
#include <linux/list_sort.h>
#include "pci.h"
#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
@ -874,14 +875,31 @@ static void pci_set_bus_msi_domain(struct pci_bus *bus)
dev_set_msi_domain(&bus->dev, d);
}
static int res_cmp(void *priv, const struct list_head *a,
const 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;
@ -960,11 +978,35 @@ 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");
/* Add initial resources to the bus */
/* Sort and coalesce contiguous windows */
list_sort(NULL, &resources, res_cmp);
resource_list_for_each_entry_safe(window, n, &resources) {
list_move_tail(&window->node, &bridge->windows);
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) {
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);