linux-kernel - C1E auto-promotion suspend/resume

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Message-ID: <CALCETrWcGE9z_oSqyi_nTGzy2WA+uaF79eTXpyba4CU9ysuZMA@mail.gmail.com>
Date:	Sun, 13 Mar 2016 18:39:03 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Len Brown <len.brown@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: C1E auto-promotion suspend/resume

Hi-

By BIOS (1.2.3 on a Dell XPS 13 9350) seems to want to enable C1E
auto-promotion (ugh!), which results in this difference across
suspend/resume according to turbostat:

-cpu3: MSR_IA32_POWER_CTL: 0x0024005d (C1E auto-promotion: DISabled)
+cpu3: MSR_IA32_POWER_CTL: 0x0024005f (C1E auto-promotion: ENabled)

Should intel_idle learn to re-disable idle promotion on resume?

--Andy