ACPI: CPPC: Fix missing PCC check for guaranteed_perf

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commit 6ea3a44cef upstream.

The current implementation overlooks the 'guaranteed_perf'
register in this check.

If the Guaranteed Performance register is located in the PCC
subspace, the function currently attempts to read it without
acquiring the lock and without sending the CMD_READ doorbell
to the firmware. This can result in reading stale data.

Fixes: 29523f0953 ("ACPI / CPPC: Add support for guaranteed performance")
Signed-off-by: Pengjie Zhang <zhangpengjie2@huawei.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20251210132227.1988380-1-zhangpengjie2@huawei.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Pengjie Zhang 2025-12-10 21:22:27 +08:00 • committed by Greg Kroah-Hartman

parent 4cb75cd4ee

commit 7e086c97dd

1 changed files with 2 additions and 1 deletions

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drivers/acpi/cppc_acpi.c

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