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ACPI: PCI: Avoid misleading _OSC messages for non-PCIe host bridges without _OSC

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After commit 7d703df7f4 ("ACPI: bus: Split _OSC evaluation out of
acpi_run_osc()"), the _OSC evaluation path now returns AE_ERROR to
negotiate_os_control() instead of propagating AE_NOT_FOUND from
acpi_evaluate_object().

This has not caused any functional issues so far, but it produces
additional misleading messages for non-PCIe host bridges without _OSC on
some Intel servers:

    kernel: ACPI: Enabled 2 GPEs in block 00 to 7F
    kernel: ACPI: PCI Root Bridge [UNC0] (domain 0000 [bus fe])
    kernel: acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI EDR HPX-Type3]
  + kernel: acpi PNP0A03:00: _OSC: OS requested [PCIeHotplug SHPCHotplug PME AER PCIeCapability LTR DPC]
  + kernel: acpi PNP0A03:00: _OSC: platform willing to grant [PCIeHotplug SHPCHotplug PME AER PCIeCapability LTR DPC]
  + kernel: acpi PNP0A03:00: _OSC: platform retains control of PCIe features (AE_ERROR)
    kernel: PCI host bridge to bus 0000:fe

Previously, negotiate_os_control() silently ignored AE_NOT_FOUND for
non-PCIe host bridges without _OSC, but after the above change, it no
longer does so.

As a result, negotiate_os_control() logs messages as if the OS had
negotiated with the platform via _OSC, even though the non-PCIe host
bridge has no _OSC method and no such negotiation actually occurs.

Skip _OSC negotiation for non-PCIe host bridges that do not define an
_OSC method before attempting to evaluate it.

Fixes: 7d703df7f4 ("ACPI: bus: Split _OSC evaluation out of acpi_run_osc()")
Link: https://lore.kernel.org/linux-acpi/d0be949d-0e21-472e-a44b-cedb1dd8695d@nec.com/
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Kazuma Kondo <kazuma-kondo@nec.com>
[ rjw: Adjust white space, drop comment and tweak the new message ]
Link: https://patch.msgid.link/20260806112052.857684-1-kazuma-kondo@nec.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Kazuma Kondo
2026-08-06 11:21:11 +00:00
committed by Rafael J. Wysocki
parent 1c24aa1bb2
commit fa608d2875
1 changed files with 7 additions and 4 deletions
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11
drivers/acpi/pci_root.c
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@@ -571,6 +571,13 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
return;
}
if (!is_pcie(root) && !is_cxl(root) && !acpi_has_method(handle, "_OSC")) {
dev_dbg(&device->dev, "Non-PCIe host bridge without _OSC, skipping\n");
*no_aspm = 1;
return;
}
support = calculate_support();
decode_osc_support(root, "OS supports", support);
@@ -612,10 +619,6 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
*/
*no_aspm = 1;
/* _OSC is optional for PCI host bridges */
if (status == AE_NOT_FOUND && !is_pcie(root))
return;
if (control) {
decode_osc_control(root, "OS requested", requested);
decode_osc_control(root, "platform willing to grant", control);