From: Mika Westerberg mika.westerberg@linux.intel.com
commit 77adf9355304f8dcf09054280af5e23fc451ab3d upstream.
Valerio and others reported that commit 84c8b58ed3ad ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug") prevents some recent LG and HP laptops from booting with endless loop of:
ACPI Error: No handler or method for GPE 08, disabling event (20190215/evgpe-835) ACPI Error: No handler or method for GPE 09, disabling event (20190215/evgpe-835) ACPI Error: No handler or method for GPE 0A, disabling event (20190215/evgpe-835) ...
What seems to happen is that during boot, after the initial PCI enumeration when EC is enabled the platform triggers ACPI Notify() to one of the root ports. The root port itself looks like this:
pci 0000:00:1b.0: PCI bridge to [bus 02-3a] pci 0000:00:1b.0: bridge window [mem 0xc4000000-0xda0fffff] pci 0000:00:1b.0: bridge window [mem 0x80000000-0xa1ffffff 64bit pref]
The BIOS has configured the root port so that it does not have I/O bridge window.
Now when the ACPI Notify() is triggered ACPI hotplug handler calls acpiphp_native_scan_bridge() for each non-hotplug bridge (as this system is using native PCIe hotplug) and pci_assign_unassigned_bridge_resources() to allocate resources.
The device connected to the root port is a PCIe switch (Thunderbolt controller) with two hotplug downstream ports. Because of the hotplug ports __pci_bus_size_bridges() tries to add "additional I/O" of 256 bytes to each (DEFAULT_HOTPLUG_IO_SIZE). This gets further aligned to 4k as that's the minimum I/O window size so each hotplug port gets 4k I/O window and the same happens for the root port (which is also hotplug port). This means 3 * 4k = 12k I/O window.
Because of this pci_assign_unassigned_bridge_resources() ends up opening a I/O bridge window for the root port at first available I/O address which seems to be in range 0x1000 - 0x3fff. Normally this range is used for ACPI stuff such as GPE bits (below is part of /proc/ioports):
1800-1803 : ACPI PM1a_EVT_BLK 1804-1805 : ACPI PM1a_CNT_BLK 1808-180b : ACPI PM_TMR 1810-1815 : ACPI CPU throttle 1850-1850 : ACPI PM2_CNT_BLK 1854-1857 : pnp 00:05 1860-187f : ACPI GPE0_BLK
However, when the ACPI Notify() happened this range was not yet reserved for ACPI/PNP (that happens later) so PCI gets it. It then starts writing to this range and accidentally stomps over GPE bits among other things causing the endless stream of messages about missing GPE handler.
This problem does not happen if "pci=hpiosize=0" is passed in the kernel command line. The reason is that then the kernel does not try to allocate the additional 256 bytes for each hotplug port.
Fix this by allocating resources directly below the non-hotplug bridges where a new device may appear as a result of ACPI Notify(). This avoids the hotplug bridges and prevents opening the additional I/O window.
Fixes: 84c8b58ed3ad ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug") Link: https://bugzilla.kernel.org/show_bug.cgi?id=203617 Link: https://lore.kernel.org/r/20191030150545.19885-1-mika.westerberg@linux.intel... Reported-by: Valerio Passini passini.valerio@gmail.com Signed-off-by: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/pci/hotplug/acpiphp_glue.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
--- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -449,8 +449,15 @@ static void acpiphp_native_scan_bridge(s
/* Scan non-hotplug bridges that need to be reconfigured */ for_each_pci_bridge(dev, bus) { - if (!hotplug_is_native(dev)) - max = pci_scan_bridge(bus, dev, max, 1); + if (hotplug_is_native(dev)) + continue; + + max = pci_scan_bridge(bus, dev, max, 1); + if (dev->subordinate) { + pcibios_resource_survey_bus(dev->subordinate); + pci_bus_size_bridges(dev->subordinate); + pci_bus_assign_resources(dev->subordinate); + } } }
@@ -480,7 +487,6 @@ static void enable_slot(struct acpiphp_s if (PCI_SLOT(dev->devfn) == slot->device) acpiphp_native_scan_bridge(dev); } - pci_assign_unassigned_bridge_resources(bus->self); } else { LIST_HEAD(add_list); int max, pass;