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Revert "PCI: acpiphp: Reassign resources on bridge if necessary"

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This reverts commit 40613da52b and the
subsequent fix to it:

  cc22522fd5 ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")

40613da52b fixed a problem where hot-adding a device with large BARs
failed if the bridge windows programmed by firmware were not large enough.

cc22522fd5 ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources()
only for non-root bus") fixed a problem with 40613da52b: an ACPI hot-add
of a device on a PCI root bus (common in the virt world) or firmware
sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron
7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs.

Unfortunately the combination of 40613da52b and cc22522fd5 caused other
problems:

  - Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails
    sometimes.

  - Dongli reported a similar problem with hot-add of SCSI disks.

  - Jonathan reported a console freeze during boot on bare metal due to an
    error in radeon GPU initialization.

Revert both patches to avoid adding these problems.  This means we will
again see the problems with hot-adding devices with large BARs and the NULL
pointer dereferences and suspend/resume issues that 40613da52b and
cc22522fd5 were intended to fix.

Fixes: 40613da52b ("PCI: acpiphp: Reassign resources on bridge if necessary")
Fixes: cc22522fd5 ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")
Reported-by: Fiona Ebner <f.ebner@proxmox.com>
Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com
Reported-by: Dongli Zhang <dongli.zhang@oracle.com>
Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com
Reported-by: Jonathan Woithe <jwoithe@just42.net>
Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Cc: <stable@vger.kernel.org>
This commit is contained in:
Bjorn Helgaas 2023-12-14 09:08:56 -06:00
parent 7ff2b7a182
commit 5df12742b7
1 changed files with 3 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/pci/hotplug/acpiphp_glue.c
View File

@ -512,15 +512,12 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
if (pass && dev->subordinate) {
check_hotplug_bridge(slot, dev);
pcibios_resource_survey_bus(dev->subordinate);
if (pci_is_root_bus(bus))
__pci_bus_size_bridges(dev->subordinate, &add_list);
__pci_bus_size_bridges(dev->subordinate,
&add_list);
}
}
}
if (pci_is_root_bus(bus))
__pci_bus_assign_resources(bus, &add_list, NULL);
else
pci_assign_unassigned_bridge_resources(bus->self);
__pci_bus_assign_resources(bus, &add_list, NULL);
}
acpiphp_sanitize_bus(bus);