[PATCH v11 7/8] cppc_acpi: print error message if CPPC is unsupported

From: Perry Yuan
Date: Tue Apr 23 2024 - 04:02:31 EST


The amd-pstate driver can fail when _CPC objects are not supported by
the CPU. However, the current error message is ambiguous (see below) and
there is no clear way for attributing the failure of the amd-pstate
driver to the lack of CPPC support.

[ 0.477523] amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

Fix this by adding an debug message to notify the user if the amd-pstate
driver failed to load due to CPPC not be supported by the CPU

Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>
Tested-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@xxxxxxx>
Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
Acked-by: Huang Rui <ray.huang@xxxxxxx>
---
drivers/acpi/cppc_acpi.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 4bfbe55553f4..3134101f31b6 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -686,8 +686,10 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)

if (!osc_sb_cppc2_support_acked) {
pr_debug("CPPC v2 _OSC not acked\n");
- if (!cpc_supported_by_cpu())
+ if (!cpc_supported_by_cpu()) {
+ pr_debug("CPPC is not supported by the CPU\n");
return -ENODEV;
+ }
}

/* Parse the ACPI _CPC table for this CPU. */
--
2.34.1