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haswell: Remove limit on package C-state

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With the XHCI controller enabled we no longer hang the
system when dropping into a package C-state so remove
the code that was disabling it.

BUG=chrome-os-partner:16862
BRANCH=none
TEST=boot wtm2 and verify package C2 residency with powertop

Change-Id: Icd60488fd2506dac04fb6ec96a77bec265b10d8c
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/50355
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
This commit is contained in:
Duncan Laurie 2013-05-07 13:19:56 -07:00 • committed by ChromeBot
commit 3ae3bd30f1
1 changed files with 1 additions and 4 deletions
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5
src/cpu/intel/haswell/haswell_init.c
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@ -427,10 +427,7 @@ static void configure_c_states(void)
msr.lo |= (1 << 26); // C1 Auto Demotion Enable
msr.lo |= (1 << 25); // C3 Auto Demotion Enable
msr.lo &= ~(1 << 10); // Disable IO MWAIT redirection
msr.lo &= ~(0xf); // Clear deepest package c-state
/* FIXME: The deepest package c-state is set to C0/C1 to work around
* platform instability when package C3 or deeper c-states are used. */
msr.lo |= 0; // Deepeset package c-state is C0/C1.
/* The deepest package c-state defaults to factory-configured value. */
wrmsr(MSR_PMG_CST_CONFIG_CONTROL, msr);
msr = rdmsr(MSR_PMG_IO_CAPTURE_BASE);