53 lines
1.7 KiB
Diff
53 lines
1.7 KiB
Diff
From e2fea58e57993ab2ed011eb35a034507347336ed Mon Sep 17 00:00:00 2001
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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
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Date: Thu, 17 Mar 2016 15:07:16 +0100
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Subject: [PATCH] Temp fix for intel_pstate oopses and lockdep report with
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Linux v4.5-1822-g63e30271b04c
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On Thursday, March 17, 2016 09:02:29 AM Josh Boyer wrote:
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> Hello,
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Hi,
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> I have an Intel Atom based NUC that is producing the following
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> backtraces on boot of Linus' tree as of last evening. This does not
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> happen with a tree with top level commit 271ecc5253e2, but does happen
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> when using the tree mentioned in the subject with top level commit
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> 63e30271b04c.
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>
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> The first backtrace appears to be a warning because the intel_pstate
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> driver is calling wrmsrl_on_cpu when interrupts are disabled? Not
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> sure on that one.
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>
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> The second backtrace is a lockdep report. Both are from the same boot.
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OK, thanks for the report.
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Can you please try the patch below?
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I'm actually unsure if we can do that safely in general for Atom because
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of the initialization, but that's what Core does anyway.
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Srinivas, Philippe, why exactly do we need the wrmsrl_on_cpu() in
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atom_set_pstate()? core_set_pstate() uses wrmsrl() and seems to be doing fine.
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---
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drivers/cpufreq/intel_pstate.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
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index cb5607495816..32d5d6456290 100644
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--- a/drivers/cpufreq/intel_pstate.c
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+++ b/drivers/cpufreq/intel_pstate.c
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@@ -587,7 +587,7 @@ static void atom_set_pstate(struct cpudata *cpudata, int pstate)
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val |= vid;
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- wrmsrl_on_cpu(cpudata->cpu, MSR_IA32_PERF_CTL, val);
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+ wrmsrl(MSR_IA32_PERF_CTL, val);
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}
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static int silvermont_get_scaling(void)
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--
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2.5.0
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