Right now when booting, on many laptops the firmware manages the PCIe
bus. As a result, when we call the _OSC ACPI method, it returns an
error code. Unfortunately the errors are not very articulate. As a
result, we show:
ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-fe])
acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI]
\_SB_.PCI0 (33DB4D5B-1FF7-401C-9657-7441C03DD766): _OSC invalid UUID
_OSC request data: 1 1f 0
acpi PNP0A08:00: _OSC failed (AE_ERROR); disabling ASPM
But we did get the capabilities mask back; the firmware is merely
managing this itself. So we really should not be showing the user a
message that looks like the firmware is broken, since it is working just
fine.
This patch supresses the error message when we're calling _OSC with the
PCIe host bridge UUID, and replaces it with a relatively innocuous
looking message that you can find if you're looking for it.
---
drivers/acpi/bus.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 262ca31..be8a91b 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -215,6 +215,8 @@ acpi_status acpi_str_to_uuid(char *str, u8 *uuid)
}
EXPORT_SYMBOL_GPL(acpi_str_to_uuid);
+static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
+
acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
{
acpi_status status;
@@ -267,9 +269,13 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
if (errors & OSC_REQUEST_ERROR)
acpi_print_osc_error(handle, context,
"_OSC request failed");
- if (errors & OSC_INVALID_UUID_ERROR)
- acpi_print_osc_error(handle, context,
- "_OSC invalid UUID");
+ if (errors & OSC_INVALID_UUID_ERROR) {
+ if (!strcasecmp(context->uuid_str, pci_osc_uuid_str))
+ pr_info("PCI PME managed by ACPI.\n");
+ else
+ acpi_print_osc_error(handle, context,
+ "_OSC invalid UUID");
+ }
if (errors & OSC_INVALID_REVISION_ERROR)
acpi_print_osc_error(handle, context,
"_OSC invalid revision");
--
2.7.4
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