kernel/linux.git/include/acpi/processor.h, branch v7.0-rc7

ACPI: processor: Do not expose global variable acpi_idle_driver

2026-01-09T21:38:22+00:00

Move the cpuidle driver check from __acpi_processor_start() to acpi_processor_power_init() which allows variable acpi_idle_driver to become static. No intentional functional impact. Signed-off-by: Huisong Li Tested-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20251223100914.2407069-7-lihuisong@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: processor: idle: Rearrange declarations in header file

2026-01-09T21:38:22+00:00

Group all of the declarations of functions that belong to the ACPI processor idle driver together in one place in processor.h. While at it, drop the unnecessary extern modifier from the declaraions of two functions. Signed-off-by: Huisong Li Tested-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20251223100914.2407069-6-lihuisong@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: processor: idle: Redefine two functions as void

2026-01-09T21:38:22+00:00

Notice that acpi_processor_power_init() and acpi_processor_power_exit() don't need to return any values because their callers don't check them anyway, so redefine those functions as void. While at it, rearrange the code in acpi_processor_power_init() to reduce the indentation level, get rid of a redundant local variable in that function, and rephrase a code comment in it. No intentional functional impact. Signed-off-by: Rafael J. Wysocki Reviewed-by: Mario Limonciello (AMD) Tested-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20251223100914.2407069-5-lihuisong@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: processor: Remove unused empty stubs of some functions

2026-01-09T21:38:22+00:00

Empty stubs are defined in processor.h for some functions provided by the ACPI processor idle driver, but those functions are only used in the main ACPI processor driver which requires the ACPI processor idle driver to be present (selecting CONFIG_ACPI_PROCESSOR causes CONFIG_ACPI_PROCESSOR_IDLE to be selected too automatically). This means that the empty stubs in question are not really necessary and if both CONFIG_ACPI_PROCESSOR and CONFIG_ACPI_PROCESSOR_IDLE are unset, the compiler complains that they are defined, but not used. Drop them to get rid of the compiler warning. Signed-off-by: Huisong Li Tested-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20251223100914.2407069-3-lihuisong@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: processor: idle: Optimize ACPI idle driver registration

2026-01-09T21:38:21+00:00

Currently, the ACPI idle driver is registered from within a CPU hotplug callback. Although this didn't cause any functional issues, this is questionable and confusing. And it is better to register the cpuidle driver when all of the CPUs have been brought up. So add a new function to initialize acpi_idle_driver based on the power management information of an available CPU and register cpuidle driver in acpi_processor_driver_init(). This commit has four changes under the commit 7a8c994cbb2d (ACPI: processor: idle: Optimize ACPI idle driver registration): 1) move acpi_processor_register_idle_driver() ahead of the driver_register(). 2) add acpi_processor_cstate_first_run_checks() before calling acpi_processor_get_power_info(). 3) squash the commit 9d68320b2bca (ACPI: processor: idle: Fix function defined but not used warning) into this change. 4) use for_each_possible_cpu(cpu) to scan all possible cpus. Signed-off-by: Huisong Li Tested-by: Borislav Petkov (AMD) [ rjw: New comment edits, changelog tweak ] Link: https://patch.msgid.link/20251223100914.2407069-2-lihuisong@huawei.com Signed-off-by: Rafael J. Wysocki

Revert "ACPI: processor: idle: Optimize ACPI idle driver registration"

2025-11-25T15:08:06+00:00

Revert commit 7a8c994cbb2d ("ACPI: processor: idle: Optimize ACPI idle driver registration") because it is reported to introduce a cpuidle regression leading to a kernel crash on a platform using the ACPI idle driver. Signed-off-by: Rafael J. Wysocki Reported-by: Borislav Petkov Tested-by: Borislav Petkov (AMD) Closes: https://lore.kernel.org/lkml/20251124200019.GIaSS5U9HhsWBotrQZ@fat_crate.local/

Revert "ACPI: processor: Remove unused empty stubs of some functions"

2025-11-25T14:05:01+00:00

Revert commit 5020d05b3476 ("ACPI: processor: Remove unused empty stubs of some functions") because it depends on a problematic one. Signed-off-by: Rafael J. Wysocki

Revert "ACPI: processor: idle: Rearrange declarations in header file"

2025-11-25T14:03:24+00:00

Revert commit bdf780fbcef5 ("ACPI: processor: idle: Rearrange declarations in header file") because it depends on a problematic one. Signed-off-by: Rafael J. Wysocki

Revert "ACPI: processor: idle: Redefine two functions as void"

2025-11-25T13:53:33+00:00

Revert commit fbd401e95e56 ("ACPI: processor: idle: Redefine two functions as void") because it depends on a problematic one. Signed-off-by: Rafael J. Wysocki

Revert "ACPI: processor: Do not expose global variable acpi_idle_driver"

2025-11-25T13:50:25+00:00

Revert commit 559f2eacc8a2 ACPI: processor: Do not expose global variable acpi_idle_driver" because it depends on a problematic one. Signed-off-by: Rafael J. Wysocki