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intel_idle: Fix SPR C6 optimization

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The Sapphire Rapids (SPR) C6 optimization was added to the end of the
'spr_idle_state_table_update()' function. However, the function has a
'return' which may happen before the optimization has a chance to run.
And this may prevent the optimization from happening.

This is an unlikely scenario, but possible if user boots with, say,
the 'intel_idle.preferred_cstates=6' kernel boot option.

This patch fixes the issue by eliminating the problematic 'return'
statement.

Fixes: 3a9cf77b60dc ("intel_idle: add core C6 optimization for SPR")
Suggested-by: Jan Beulich <jbeulich@suse.com>
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
[ rjw: Minor changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Artem Bityutskiy 2022-04-27 09:08:53 +03:00 committed by Rafael J. Wysocki
parent 39c184a6a9
commit 7eac3bd38d
1 changed files with 3 additions and 5 deletions
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8
drivers/idle/intel_idle.c
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@ -1581,11 +1581,9 @@ static void __init spr_idle_state_table_update(void)
unsigned long long msr;
/* Check if user prefers C1E over C1. */
if (preferred_states_mask & BIT(2)) {
if (preferred_states_mask & BIT(1))
/* Both can't be enabled, stick to the defaults. */
return;
if ((preferred_states_mask & BIT(2)) &&
!(preferred_states_mask & BIT(1))) {
/* Disable C1 and enable C1E. */
spr_cstates[0].flags |= CPUIDLE_FLAG_UNUSABLE;
spr_cstates[1].flags &= ~CPUIDLE_FLAG_UNUSABLE;