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| author | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2022-04-27 09:08:53 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-04-27 20:36:47 +0200 |
| commit | 7eac3bd38d18cd3317756649921b8264ddfee692 (patch) | |
| tree | 07007493d1fad2dff1b31fcee21cca8859afffd9 /drivers/idle | |
| parent | 39c184a6a9a7a99950b321d55fe713175cf1d404 (diff) | |
| download | lwn-7eac3bd38d18cd3317756649921b8264ddfee692.tar.gz lwn-7eac3bd38d18cd3317756649921b8264ddfee692.zip | |
intel_idle: Fix SPR C6 optimization
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>
Diffstat (limited to 'drivers/idle')
| -rw-r--r-- | drivers/idle/intel_idle.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index cf5ed4c1d02c..47551ab73ca8 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -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; |