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-rw-r--r--drivers/cpufreq/intel_pstate.c27
1 files changed, 21 insertions, 6 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 5ab6a4fe93aa..75a5408e6981 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -2476,6 +2476,7 @@ static bool __init intel_pstate_no_acpi_pss(void)
kfree(pss);
}
+ pr_debug("ACPI _PSS not found\n");
return true;
}
@@ -2486,9 +2487,14 @@ static bool __init intel_pstate_no_acpi_pcch(void)
status = acpi_get_handle(NULL, "\\_SB", &handle);
if (ACPI_FAILURE(status))
- return true;
+ goto not_found;
+
+ if (acpi_has_method(handle, "PCCH"))
+ return false;
- return !acpi_has_method(handle, "PCCH");
+not_found:
+ pr_debug("ACPI PCCH not found\n");
+ return true;
}
static bool __init intel_pstate_has_acpi_ppc(void)
@@ -2503,6 +2509,7 @@ static bool __init intel_pstate_has_acpi_ppc(void)
if (acpi_has_method(pr->handle, "_PPC"))
return true;
}
+ pr_debug("ACPI _PPC not found\n");
return false;
}
@@ -2540,8 +2547,10 @@ static bool __init intel_pstate_platform_pwr_mgmt_exists(void)
id = x86_match_cpu(intel_pstate_cpu_oob_ids);
if (id) {
rdmsrl(MSR_MISC_PWR_MGMT, misc_pwr);
- if ( misc_pwr & (1 << 8))
+ if (misc_pwr & (1 << 8)) {
+ pr_debug("Bit 8 in the MISC_PWR_MGMT MSR set\n");
return true;
+ }
}
idx = acpi_match_platform_list(plat_info);
@@ -2607,22 +2616,28 @@ static int __init intel_pstate_init(void)
}
} else {
id = x86_match_cpu(intel_pstate_cpu_ids);
- if (!id)
+ if (!id) {
+ pr_info("CPU ID not supported\n");
return -ENODEV;
+ }
copy_cpu_funcs((struct pstate_funcs *)id->driver_data);
}
- if (intel_pstate_msrs_not_valid())
+ if (intel_pstate_msrs_not_valid()) {
+ pr_info("Invalid MSRs\n");
return -ENODEV;
+ }
hwp_cpu_matched:
/*
* The Intel pstate driver will be ignored if the platform
* firmware has its own power management modes.
*/
- if (intel_pstate_platform_pwr_mgmt_exists())
+ if (intel_pstate_platform_pwr_mgmt_exists()) {
+ pr_info("P-states controlled by the platform\n");
return -ENODEV;
+ }
if (!hwp_active && hwp_only)
return -ENOTSUPP;