kernel/drivers/cpuidle/cpuidle.c, branch master

sched: idle: Make skipping governor callbacks more consistent

2026-03-10T15:03:02Z

If the cpuidle governor .select() callback is skipped because there is only one idle state in the cpuidle driver, the .reflect() callback should be skipped as well, at least for consistency (if not for correctness), so do it. Fixes: e5c9ffc6ae1b ("cpuidle: Skip governor when only one idle state is available") Signed-off-by: Rafael J. Wysocki Reviewed-by: Christian Loehle Reviewed-by: Aboorva Devarajan Reviewed-by: Frederic Weisbecker Link: https://patch.msgid.link/12857700.O9o76ZdvQC@rafael.j.wysocki

cpuidle: Skip governor when only one idle state is available

2026-02-17T14:49:02Z

On certain platforms (PowerNV systems without a power-mgt DT node), cpuidle may register only a single idle state. In cases where that single state is a polling state (state 0), the ladder governor may incorrectly treat state 1 as the first usable state and pass an out-of-bounds index. This can lead to a NULL enter callback being invoked, ultimately resulting in a system crash. [ 13.342636] cpuidle-powernv : Only Snooze is available [ 13.351854] Faulting instruction address: 0x00000000 [ 13.376489] NIP [0000000000000000] 0x0 [ 13.378351] LR [c000000001e01974] cpuidle_enter_state+0x2c4/0x668 Fix this by adding a bail-out in cpuidle_select() that returns state 0 directly when state_count <= 1, bypassing the governor and keeping the tick running. Fixes: dc2251bf98c6 ("cpuidle: Eliminate the CPUIDLE_DRIVER_STATE_START symbol") Signed-off-by: Aboorva Devarajan Reviewed-by: Christian Loehle Link: https://patch.msgid.link/20260216185005.1131593-2-aboorvad@linux.ibm.com Signed-off-by: Rafael J. Wysocki

sched: idle: Respect the CPU system wakeup QoS limit for s2idle

2025-11-25T18:01:29Z

A CPU system wakeup QoS limit may have been requested by user space. To avoid breaking this constraint when entering a low power state during s2idle, let's start to take into account the QoS limit. Acked-by: Peter Zijlstra (Intel) Reviewed-by: Dhruva Gole Reviewed-by: Kevin Hilman (TI) Tested-by: Kevin Hilman (TI) Signed-off-by: Ulf Hansson Link: https://patch.msgid.link/20251125112650.329269-5-ulf.hansson@linaro.org Signed-off-by: Rafael J. Wysocki

cpuidle: Fail cpuidle device registration if there is one already

2025-09-20T11:08:54Z

Refuse to register a cpuidle device if the given CPU has a cpuidle device already and print a message regarding it. Without this, an attempt to register a new cpuidle device without unregistering the existing one leads to the removal of the existing cpuidle device without removing its sysfs interface. Signed-off-by: Rafael J. Wysocki

cpuidle: Do not return from cpuidle_play_dead() on callback failures

2024-11-19T20:46:51Z

If the :enter_dead() idle state callback fails for a certain state, there may be still a shallower state for which it will work. Because the only caller of cpuidle_play_dead(), native_play_dead(), falls back to hlt_play_dead() if it returns an error, it should better try all of the idle states for which :enter_dead() is present before failing, so change it accordingly. Also notice that the :enter_dead() state callback is not expected to return on success (the CPU should be "dead" then), so make cpuidle_play_dead() ignore its return value. Signed-off-by: Rafael J. Wysocki Reviewed-by: Mario Limonciello Tested-by: Mario Limonciello # 6.12-rc7 Reviewed-by: Gautham R. Shenoy Link: https://patch.msgid.link/3318440.aeNJFYEL58@rjwysocki.net

cpuidle: Correct some typos in comments

2024-10-18T16:44:32Z

Fixed some confusing typos that were currently identified with codespell, the details are as follows: -in the code comments: drivers/cpuidle/cpuidle-arm.c:142: registeration ==> registration drivers/cpuidle/cpuidle-qcom-spm.c:51: accidently ==> accidentally drivers/cpuidle/cpuidle.c:409: dependant ==> dependent drivers/cpuidle/driver.c:264: occuring ==> occurring drivers/cpuidle/driver.c:299: occuring ==> occurring Signed-off-by: Shen Lichuan Link: https://patch.msgid.link/20240927081018.8608-1-shenlichuan@vivo.com Signed-off-by: Rafael J. Wysocki

cpuidle: remove dead code from cpuidle_enter_state()

2024-08-22T19:03:52Z

Checking for index < 0 is useless because the find_deepest_state() function never really returns a negative value. Since this hasn't been reported in over 9 years it's dead code, so remove it. Signed-off-by: Dhruva Gole Link: https://patch.msgid.link/20240821114250.1416421-1-d-gole@ti.com [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki

x86/mm: delete unused cpu argument to leave_mm()

2024-02-22T18:24:41Z

The argument is unused since commit 3d28ebceaffa ("x86/mm: Rework lazy TLB to track the actual loaded mm"), delete it. Link: https://lkml.kernel.org/r/20240126080644.1714297-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed Cc: Andy Lutomirski Cc: Borislav Petkov (AMD) Cc: Dave Hansen Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Andrew Morton

cpuidle: Use local_clock_noinstr()

2023-06-05T19:11:09Z

With the introduction of local_clock_noinstr(), local_clock() itself is no longer marked noinstr, use the correct function. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Rafael J. Wysocki Tested-by: Michael Kelley # Hyper-V Link: https://lore.kernel.org/r/20230519102716.045980863@infradead.org

cpuidle: move to use bus_get_dev_root()

2023-03-22T19:25:23Z

Direct access to the struct bus_type dev_root pointer is going away soon so replace that with a call to bus_get_dev_root() instead, which is what it is there for. This allows us to clean up the cpuidle_add_interface() call a bit as it was only called in one place, with the same argument so just put that into the function itself. Note that cpuidle_remove_interface() should also probably be removed in the future as there are no callers of it for some reason. Cc: Daniel Lezcano Cc: linux-pm@vger.kernel.org Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20230322090557.2943479-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman