lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Fri, 22 Mar 2019 15:45:20 -0700
From:   Srinivas Pandruvada <>
        Srinivas Pandruvada <>,
        "4 . 20+" <>
Subject: [PATCH 2/2] cpufreq: intel_pstate: Also use cppc nominal_perf for base_frequency

ACPI specifications stat that if the "Guaranteed Performance Register" is
not implemented, OSPM assumes guaranteed performance is always equal to
nominal performance. So for invalid and unimplemented guaranteed
performance register, use nominal performance as guaranteed performance.

This change will fallback to nominal_perf when guranteed_perf is invalid.
If nominal_perf is also invalid, then fallback to existing implementation,
which is to read from HWP Capabilities MSR.

Fixes: 86d333a8cc7f ("cpufreq: intel_pstate: Add base_frequency attribute")
Signed-off-by: Srinivas Pandruvada <>
Cc: 4.20+ <> # 4.20+
 drivers/cpufreq/intel_pstate.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 7b4b0a7ac68b..e16dea241c55 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -385,6 +385,9 @@ static int intel_pstate_get_cppc_guranteed(int cpu)
 	if (ret)
 		return ret;
+	if (!cppc_perf.guaranteed_perf)
+		return cppc_perf.nominal_perf;
 	return cppc_perf.guaranteed_perf;

Powered by blists - more mailing lists