[Xen-devel] [PATCH 4/4] xen/acpi: Workaround broken BIOSes exporting non-existing C-states.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

We did a similar check for the P-states but did not do it for
the C-states. What we want to do is ignore cases where the DSDT
has definition for sixteen CPUs, but the machine only has eight
CPUs and we get:
xen-acpi-processor: (CX): Hypervisor error (-22) for ACPI CPU14

Reported-by: Tobias Geiger <tobias.geiger@xxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 drivers/xen/xen-acpi-processor.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
index 174b565..0b48579 100644
--- a/drivers/xen/xen-acpi-processor.c
+++ b/drivers/xen/xen-acpi-processor.c
@@ -128,7 +128,10 @@ static int push_cxx_to_hypervisor(struct acpi_processor 
*_pr)
                        pr_debug("     C%d: %s %d uS\n",
                                 cx->type, cx->desc, (u32)cx->latency);
                }
-       } else
+       } else if (ret != -EINVAL)
+               /* EINVAL means the ACPI ID is incorrect - meaning the ACPI
+                * table is referencing a non-existing CPU - which can happen
+                * with broken ACPI tables. */
                pr_err(DRV_NAME "(CX): Hypervisor error (%d) for ACPI CPU%u\n",
                       ret, _pr->acpi_id);
 
-- 
1.7.7.5


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