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From: Paul Menzel <>
To: Thomas Gleixner <>,
	Ingo Molnar <>, Borislav Petkov <>,, "H. Peter Anvin" <>
Cc: "Rafael J . Wysocki" <>,
	Paul Menzel <>,
Subject: [PATCH 1/2] x86: intel_epb: Mention firmware in ENERGY_PERF_BIAS warning
Date: Tue, 17 Aug 2021 16:38:29 +0200	[thread overview]
Message-ID: <> (raw)

The warning

    ENERGY_PERF_BIAS: Set to 'normal', was 'performance'

is shown on all my Intel systems, and for a normal user it’s unclear
what to do about it. Change it to

    ENERGY_PERF_BIAS: Set to 'normal', was 'performance' (unchanged by firmware)

so it’s clear, that it might be possible to change the setting in the
system firmware.

Signed-off-by: Paul Menzel <>
 arch/x86/kernel/cpu/intel_epb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/intel_epb.c b/arch/x86/kernel/cpu/intel_epb.c
index f4dd73396f28..3f8c0b59d08a 100644
--- a/arch/x86/kernel/cpu/intel_epb.c
+++ b/arch/x86/kernel/cpu/intel_epb.c
@@ -91,7 +91,7 @@ static void intel_epb_restore(void)
 		val = epb & EPB_MASK;
-			pr_warn_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance'\n");
+			pr_warn_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance' (unchanged by firmware)\n");
 	wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, (epb & ~EPB_MASK) | val);

             reply	other threads:[~2021-08-17 14:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17 14:38 Paul Menzel [this message]
2021-08-17 14:38 ` [PATCH 2/2] x86: intel_epb: Decrease ENERGY_PERF_BIAS warning to info log message Paul Menzel

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