cpufreq: acpi-cpufreq: Report if CPU doesn't support boost technologies

[ Upstream commit 1222d527 ]

There is some rare cases where CPB (and possibly IDA) are missing on
processors.

This is the case fixed by commit f7f3dc00 ("x86/cpu/AMD: Fix
erratum 1076 (CPB bit)") and following.

In such context, the boost status isn't reported by
/sys/devices/system/cpu/cpufreq/boost.

This commit is about printing a message to report that the CPU
doesn't expose the boost capabilities.

This message could help debugging platforms hit by this phenomena.
Signed-off-by: Erwan Velu <e.velu@criteo.com>
[ rjw: Change the message text somewhat ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/cpufreq/acpi-cpufreq.c

@@ -909,8 +909,10 @@ static void __init acpi_cpufreq_boost_init(void)
 {
 	int ret;
 
-	if (!(boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA)))
+	if (!(boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA))) {
+		pr_debug("Boost capabilities not present in the processor\n");
 		return;
+	}
 
 	acpi_cpufreq_driver.set_boost = set_boost;
 	acpi_cpufreq_driver.boost_enabled = boost_state(0);