kernel/linux.git/drivers/cpufreq/amd-pstate.c, branch linux-7.1.y

cpufreq/amd-pstate: Fix setting EPP in performance mode

2026-06-02T17:32:06+00:00

EPP 0 is the only supported value in the performance policy. commit 798c47593cca ("cpufreq/amd-pstate: Add support for platform profile class") changed this while adding platform profile support to the dynamic EPP feature, but this actually wasn't necessary since platform profile writes disable manual EPP writes. Restore allowing writing EPP of 0 when in performance mode. Reviewed-by: Marco Scardovi Tested-by: Marco Scardovi Reported-by: Stuart Meckle Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221473 Closes: https://gitlab.freedesktop.org/upower/power-profiles-daemon/-/work_items/190 Fixes: 798c47593cca ("cpufreq/amd-pstate: Add support for platform profile class") Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Drop Kconfig option for dynamic EPP

2026-05-14T13:47:48+00:00

There are some performance issues being identified by dynamic EPP and we don't want to have distributions turning it on by default exposing them to users at this time. Drop the kconfig option, and require an explicit opt in from kernel command line or runtime sysfs option to turn it on. Reported-by: Viktor Jägersküpper Closes: https://lore.kernel.org/linux-pm/14a87c99-785c-4b16-bfce-35ecbf053448@freenet.de/ Reported-by: Stuart Meckle Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221473 Signed-off-by: Mario Limonciello Reviewed-by: K Prateek Nayak Link: https://lore.kernel.org/r/20260512221947.1652988-1-mario.limonciello@amd.com (fix sysfs file path) Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Use "epp_default_dc" as default when dynamic_epp is disabled

2026-05-08T05:30:50+00:00

If "dynamic_epp" is disabled, the driver initialization and the default EPP selection from sysfs currently sets the EPP based on the power supply state of the system at that time but there is no power supply callbacks registered to toggle it when the power supply state changes. This can lead to faster battery drain on platforms that start off while being plugged to the wall but later move to battery power since the EPP stays at AMD_CPPC_EPP_PERFORMANCE. Use "epp_default_dc" as the default EPP selection when dynamic_epp is disabled, restoring older behavior. On servers, this defaults to AMD_CPPC_EPP_PERFORMANCE and on other platforms, it defaults to AMD_CPPC_EPP_BALANCE_PERFORMANCE. Fixes: e30ca6dd5345 ("cpufreq/amd-pstate: Add dynamic energy performance preference") Reviewed-by: Mario Limonciello Signed-off-by: K Prateek Nayak Link: https://lore.kernel.org/r/20260508051748.10484-6-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Reorder notifier unregistration and floor perf reset

2026-05-08T05:30:50+00:00

An active power supply notifier can race with amd_pstate_epp_cpu_exit() trying to reset the floor perf and can overwrite the floor perf set in MSR_AMD_CPPC_REQ. Unregister the notifier before setting the floor perf to prevent the rare race. Fixes: e30ca6dd5345 ("cpufreq/amd-pstate: Add dynamic energy performance preference") Reviewed-by: Mario Limonciello Signed-off-by: K Prateek Nayak Link: https://lore.kernel.org/r/20260508051748.10484-5-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Allow writes to dynamic_epp when state isn't modified

2026-05-08T05:30:50+00:00

Writing the current "dynamic_epp" state to sysfs fails with -EINVAL even though the desired result was achieved. Allow writes to "dynamic_epp" that does not modify the state. Fixes: e30ca6dd5345 ("cpufreq/amd-pstate: Add dynamic energy performance preference") Reviewed-by: Mario Limonciello Signed-off-by: K Prateek Nayak Link: https://lore.kernel.org/r/20260508051748.10484-4-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Return -ENOMEM on failure to allocate profile_name

2026-05-08T05:30:50+00:00

Failure to allocate profile name will return -EINVAL from platform_profile_register() while in fact, it is a failure to allocate memory for the profile_name string. Return -ENOMEM when kasprintf() fails to allocate profile_name string. Fixes: e30ca6dd5345 ("cpufreq/amd-pstate: Add dynamic energy performance preference") Reviewed-by: Mario Limonciello Signed-off-by: K Prateek Nayak Link: https://lore.kernel.org/r/20260508051748.10484-3-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD)

cpufreq/amd-pstate: Grab "amd_pstate_driver_lock" when toggling dynamic_epp

2026-05-08T05:30:50+00:00

Concurrently changing driver mode and dynamic_epp with: echo passive > /sys/devices/system/cpu/amd_pstate/status& echo disable > /sys/devices/system/cpu/amd_pstate/dynamic_epp& hits the WARN_ON_ONCE() in static_key_disable_cpuslocked() and hangs the system since both sysfs writes are trying to do amd_pstate_change_driver_mode() without any synchronization. Grab the "amd_pstate_driver_lock" mutex when modifying "dynamic_epp" to prevent the two paths from racing with each other. Add a lockdep assertion for "amd_pstate_driver_lock" in amd_pstate_change_driver_mode() to formalize the dependency. Since "cppc_mode" is stable under "amd_pstate_driver_lock", only reload the driver when in "AMD_PSTATE_ACTIVE" mode and reject all writes when in passive or guided mode, or if the driver is not loaded, since only active mode operates on EPP. Fixes: e30ca6dd5345 ("cpufreq/amd-pstate: Add dynamic energy performance preference") Reviewed-by: Mario Limonciello Signed-off-by: K Prateek Nayak Link: https://lore.kernel.org/r/20260508051748.10484-2-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD)

Merge tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-17T16:43:12+00:00

Pull tracing updates from Steven Rostedt: - Fix printf format warning for bprintf sunrpc uses a trace_printk() that triggers a printf warning during the compile. Move the __printf() attribute around for when debugging is not enabled the warning will go away - Remove redundant check for EVENT_FILE_FL_FREED in event_filter_write() The FREED flag is checked in the call to event_file_file() and then checked again right afterward, which is unneeded - Clean up event_file_file() and event_file_data() helpers These helper functions played a different role in the past, but now with eventfs, the READ_ONCE() isn't needed. Simplify the code a bit and also add a warning to event_file_data() if the file or its data is not present - Remove updating file->private_data in tracing open All access to the file private data is handled by the helper functions, which do not use file->private_data. Stop updating it on open - Show ENUM names in function arguments via BTF in function tracing When showing the function arguments when func-args option is set for function tracing, if one of the arguments is found to be an enum, show the name of the enum instead of its number - Add new trace_call__##name() API for tracepoints Tracepoints are enabled via static_branch() blocks, where when not enabled, there's only a nop that is in the code where the execution will just skip over it. When tracing is enabled, the nop is converted to a direct jump to the tracepoint code. Sometimes more calculations are required to be performed to update the parameters of the tracepoint. In this case, trace_##name##_enabled() is called which is a static_branch() that gets enabled only when the tracepoint is enabled. This allows the extra calculations to also be skipped by the nop: if (trace_foo_enabled()) { x = bar(); trace_foo(x); } Where the x=bar() is only performed when foo is enabled. The problem with this approach is that there's now two static_branch() calls. One for checking if the tracepoint is enabled, and then again to know if the tracepoint should be called. The second one is redundant Introduce trace_call__foo() that will call the foo() tracepoint directly without doing a static_branch(): if (trace_foo_enabled()) { x = bar(); trace_call__foo(); } - Update various locations to use the new trace_call__##name() API - Move snapshot code out of trace.c Cleaning up trace.c to not be a "dump all", move the snapshot code out of it and into a new trace_snapshot.c file - Clean up some "%*.s" to "%*s" - Allow boot kernel command line options to be called multiple times Have options like: ftrace_filter=foo ftrace_filter=bar ftrace_filter=zoo Equal to: ftrace_filter=foo,bar,zoo - Fix ipi_raise event CPU field to be a CPU field The ipi_raise target_cpus field is defined as a __bitmask(). There is now a __cpumask() field definition. Update the field to use that - Have hist_field_name() use a snprintf() and not a series of strcat() It's safer to use snprintf() that a series of strcat() - Fix tracepoint regfunc balancing A tracepoint can define a "reg" and "unreg" function that gets called before the tracepoint is enabled, and after it is disabled respectively. But on error, after the "reg" func is called and the tracepoint is not enabled, the "unreg" function is not called to tear down what the "reg" function performed - Fix output that shows what histograms are enabled Event variables are displayed incorrectly in the histogram output Instead of "sched.sched_wakeup.$var", it is showing "$sched.sched_wakeup.var" where the '$' is in the incorrect location - Some other simple cleanups * tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (24 commits) selftests/ftrace: Add test case for fully-qualified variable references tracing: Fix fully-qualified variable reference printing in histograms tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() tracing: Rebuild full_name on each hist_field_name() call tracing: Report ipi_raise target CPUs as cpumask tracing: Remove duplicate latency_fsnotify() stub tracing: Preserve repeated trace_trigger boot parameters tracing: Append repeated boot-time tracing parameters tracing: Remove spurious default precision from show_event_trigger/filter formats cpufreq: Use trace_call__##name() at guarded tracepoint call sites tracing: Remove tracing_alloc_snapshot() when snapshot isn't defined tracing: Move snapshot code out of trace.c and into trace_snapshot.c mm: damon: Use trace_call__##name() at guarded tracepoint call sites btrfs: Use trace_call__##name() at guarded tracepoint call sites spi: Use trace_call__##name() at guarded tracepoint call sites i2c: Use trace_call__##name() at guarded tracepoint call sites kernel: Use trace_call__##name() at guarded tracepoint call sites tracepoint: Add trace_call__##name() API tracing: trace_mmap.h: fix a kernel-doc warning tracing: Pretty-print enum parameters in function arguments ...

Merge tag 'amd-pstate-v7.1-2026-04-02' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux

2026-04-04T18:55:56+00:00

Pull amd-pstate new content for 7.1 (2026-04-02) from Mario Limonciello: "Add support for new features: * CPPC performance priority * Dynamic EPP * Raw EPP * New unit tests for new features Fixes for: * PREEMPT_RT * sysfs files being present when HW missing * Broken/outdated documentation" * tag 'amd-pstate-v7.1-2026-04-02' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux: (22 commits) MAINTAINERS: amd-pstate: Step down as maintainer, add Prateek as reviewer cpufreq: Pass the policy to cpufreq_driver->adjust_perf() cpufreq/amd-pstate: Pass the policy to amd_pstate_update() cpufreq/amd-pstate-ut: Add a unit test for raw EPP cpufreq/amd-pstate: Add support for raw EPP writes cpufreq/amd-pstate: Add support for platform profile class cpufreq/amd-pstate: add kernel command line to override dynamic epp cpufreq/amd-pstate: Add dynamic energy performance preference Documentation: amd-pstate: fix dead links in the reference section cpufreq/amd-pstate: Cache the max frequency in cpudata Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count} Documentation/amd-pstate: List amd_pstate_prefcore_ranking sysfs file Documentation/amd-pstate: List amd_pstate_hw_prefcore sysfs file amd-pstate-ut: Add a testcase to validate the visibility of driver attributes amd-pstate-ut: Add module parameter to select testcases amd-pstate: Introduce a tracepoint trace_amd_pstate_cppc_req2() amd-pstate: Add sysfs support for floor_freq and floor_count amd-pstate: Add support for CPPC_REQ2 and FLOOR_PERF x86/cpufeatures: Add AMD CPPC Performance Priority feature. amd-pstate: Make certain freq_attrs conditionally visible ...

cpufreq: Pass the policy to cpufreq_driver->adjust_perf()

2026-04-02T16:30:24+00:00

cpufreq_cpu_get() can sleep on PREEMPT_RT in presence of concurrent writer(s), however amd-pstate depends on fetching the cpudata via the policy's driver data which necessitates grabbing the reference. Since schedutil governor can call "cpufreq_driver->update_perf()" during sched_tick/enqueue/dequeue with rq_lock held and IRQs disabled, fetching the policy object using the cpufreq_cpu_get() helper in the scheduler fast-path leads to "BUG: scheduling while atomic" on PREEMPT_RT [1]. Pass the cached cpufreq policy object in sg_policy to the update_perf() instead of just the CPU. The CPU can be inferred using "policy->cpu". The lifetime of cpufreq_policy object outlasts that of the governor and the cpufreq driver (allocated when the CPU is onlined and only reclaimed when the CPU is offlined / the CPU device is removed) which makes it safe to be referenced throughout the governor's lifetime. Closes:https://lore.kernel.org/all/20250731092316.3191-1-spasswolf@web.de/ [1] Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State") Reported-by: Bert Karwatzki Acked-by: Viresh Kumar Signed-off-by: K Prateek Nayak Acked-by: Gary Guo # Rust Reviewed-by: Gautham R. Shenoy Reviewed-by: Zhongqiu Han Link: https://lore.kernel.org/r/20260316081849.19368-3-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD)