linux/drivers/acpi/processor_idle.c, branch v6.17

ACPI: processor: Rescan "dead" SMT siblings during initialization

2025-06-07T12:23:22Z

Make acpi_processor_driver_init() call arch_cpu_rescan_dead_smt_siblings(), via a new wrapper function called acpi_idle_rescan_dead_smt_siblings(), after successfully initializing the driver, to allow the "dead" SMT siblings to go into deep idle states, which is necessary for the processor to be able to reach deep package C-states (like PC10) going forward, so that power can be reduced sufficiently in suspend-to-idle, among other things. However, do it only if the ACPI idle driver is the current cpuidle driver (otherwise it is assumed that another cpuidle driver will take care of this) and avoid doing it on architectures other than x86. Signed-off-by: Rafael J. Wysocki Tested-by: Artem Bityutskiy Link: https://patch.msgid.link/2005721.PYKUYFuaPT@rjwysocki.net

ACPI: processor: idle: Remove redundant pr->power.count assignment

2025-04-10T12:17:12Z

pr->power.count stands for the number of valid processor cstates. And it is correctly set with the return value of acpi_processor_power_verify(), in acpi_processor_get_cstate_info(). Remove the redundant logic that unnecessarily overrides pr->power.count value. No functional change intended. Signed-off-by: Zhang Rui Link: https://patch.msgid.link/20250409005026.1932637-3-rui.zhang@intel.com [ rjw: Removed unused variable, fixed up white space ] Signed-off-by: Rafael J. Wysocki

ACPI: processor: idle: Set pr->flags.power unconditionally

2025-04-09T14:16:38Z

acpi_processor_get_power_info_default() ensures that the processor's ACPI_STATE_C1 state is always valid. Consequently, the pr->flags.power should be set unconditionally after this. Remove conditional checks and directly set pr->flags.power. No functional change. Signed-off-by: Zhang Rui Link: https://patch.msgid.link/20250409005026.1932637-2-rui.zhang@intel.com Signed-off-by: Rafael J. Wysocki

ACPI: processor: idle: Remove obsolete comment

2025-04-09T12:52:55Z

Since commit 496121c02127 ("ACPI: processor: idle: Allow probing on platforms with one ACPI C-state"), the comment doesn't reflect the code anymore; remove it. Signed-off-by: Giovanni Gherdovich Acked-by: Zhang Rui Link: https://patch.msgid.link/20250328143040.9348-2-ggherdovich@suse.cz Signed-off-by: Rafael J. Wysocki

ACPI: processor: idle: Return an error if both P_LVL{2,3} idle states are invalid

2025-03-31T11:59:04Z

Prior to commit 496121c02127 ("ACPI: processor: idle: Allow probing on platforms with one ACPI C-state"), the acpi_idle driver wouldn't load on systems without a valid C-State at least as deep as C2. The behavior was desirable for guests on hypervisors such as VMWare ESXi, which by default don't have the _CST ACPI method, and set the C2 and C3 latencies to 101 and 1001 microseconds respectively via the FADT, to signify they're unsupported. Since the above change though, these virtualized deployments end up loading acpi_idle, and thus entering the default C1 C-State set by acpi_processor_get_power_info_default(); this is undesirable for a system that's communicating to the OS it doesn't want C-States (missing _CST, and invalid C2/C3 in FADT). Make acpi_processor_get_power_info_fadt() return -ENODEV in that case, so that acpi_processor_get_cstate_info() exits early and doesn't set pr->flags.power = 1. Fixes: 496121c02127 ("ACPI: processor: idle: Allow probing on platforms with one ACPI C-state") Signed-off-by: Giovanni Gherdovich Reviewed-by: Zhang Rui Link: https://patch.msgid.link/20250328143040.9348-1-ggherdovich@suse.cz [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki

ACPI/processor_idle: Add FFH state handling

2025-02-05T18:44:52Z

Recent Intel platforms will depend on the idle driver to pass the correct hint for playing dead via mwait_play_dead_with_hint(). Expand the existing enter_dead interface with handling for FFH states and pass the MWAIT hint to the mwait_play_dead code. Suggested-by: Gautham R. Shenoy Signed-off-by: Patryk Wlazlyn Signed-off-by: Artem Bityutskiy Signed-off-by: Dave Hansen Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/all/20250205155211.329780-3-artem.bityutskiy%40linux.intel.com

Merge tag 'acpi-6.13-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2024-11-27T22:50:31Z

Pull more ACPI updates from Rafael Wysocki: "These add a common init function for arch-specific ACPI initialization, clean up idle states initialization in the ACPI processor_idle driver and update quirks: - Introduce acpi_arch_init() for architecture-specific ACPI subsystem initialization (Miao Wang) - Clean up Asus quirks in acpi_quirk_skip_dmi_ids[] and add a quirk to skip I2C clients on Acer Iconia One 8 A1-840 (Hans de Goede) - Make the ACPI processor_idle driver use acpi_idle_play_dead() for all idle states regardless of their types (Rafael Wysocki)" * tag 'acpi-6.13-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI: introduce acpi_arch_init() ACPI: x86: Clean up Asus entries in acpi_quirk_skip_dmi_ids[] ACPI: x86: Add skip i2c clients quirk for Acer Iconia One 8 A1-840 ACPI: processor_idle: Use acpi_idle_play_dead() for all C-states

cpuidle: Change :enter_dead() driver callback return type to void

2024-11-19T20:46:51Z

After a previous change, cpuidle_play_dead(), which is the only caller of idle state :enter_dead() callbacks, ignores their return values, so they may as well be void. Suggested-by: Peter Zijlstra Signed-off-by: Rafael J. Wysocki Reviewed-by: Gautham R. Shenoy Reviewed-by: Mario Limonciello Link: https://patch.msgid.link/2285569.iZASKD2KPV@rjwysocki.net

ACPI: processor_idle: Use acpi_idle_play_dead() for all C-states

2024-11-19T20:43:51Z

Notice that acpi_processor_setup_cstates() can set state->enter_dead to acpi_idle_play_dead() for all C-states unconditionally and remove the confusing C-state type check done before setting it. No intentional functional impact. Suggested-by: Peter Zijlstra Signed-off-by: Rafael J. Wysocki Reviewed-by: Mario Limonciello Tested-by: Mario Limonciello # 6.12-rc7 Acked-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/2373563.ElGaqSPkdT@rjwysocki.net

ACPI: processor_idle: Fix invalid comparison with insertion sort for latency

2024-07-02T18:35:29Z

The acpi_cst_latency_cmp() comparison function currently used for sorting C-state latencies does not satisfy transitivity, causing incorrect sorting results. Specifically, if there are two valid acpi_processor_cx elements A and B and one invalid element C, it may occur that A < B, A = C, and B = C. Sorting algorithms assume that if A < B and A = C, then C < B, leading to incorrect ordering. Given the small size of the array (<=8), we replace the library sort function with a simple insertion sort that properly ignores invalid elements and sorts valid ones based on latency. This change ensures correct ordering of the C-state latencies. Fixes: 65ea8f2c6e23 ("ACPI: processor idle: Fix up C-state latency if not ordered") Reported-by: Julian Sikorski Closes: https://lore.kernel.org/lkml/70674dc7-5586-4183-8953-8095567e73df@gmail.com Signed-off-by: Kuan-Wei Chiu Tested-by: Julian Sikorski Cc: All applicable Link: https://patch.msgid.link/20240701205639.117194-1-visitorckw@gmail.com Signed-off-by: Rafael J. Wysocki