kernel/linux.git/drivers/cpufreq/intel_pstate.c, branch v5.16

cpufreq: intel_pstate: ITMT support for overclocked system

2021-11-23T13:11:18+00:00

On systems with overclocking enabled, CPPC Highest Performance can be hard coded to 0xff. In this case even if we have cores with different highest performance, ITMT can't be enabled as the current implementation depends on CPPC Highest Performance. On such systems we can use MSR_HWP_CAPABILITIES maximum performance field when CPPC.Highest Performance is 0xff. Due to legacy reasons, we can't solely depend on MSR_HWP_CAPABILITIES as in some older systems CPPC Highest Performance is the only way to identify different performing cores. Reported-by: Michael Larabel Signed-off-by: Srinivas Pandruvada Tested-by: Michael Larabel Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Fix active mode offline/online EPP handling

2021-11-23T13:02:11+00:00

After commit 4adcf2e5829f ("cpufreq: intel_pstate: Add ->offline and ->online callbacks") the EPP value set by the "performance" scaling algorithm in the active mode is not restored after an offline/online cycle which replaces it with the saved EPP value coming from user space. Address this issue by forcing intel_pstate_hwp_set() to set a new EPP value when it runs first time after online. Fixes: 4adcf2e5829f ("cpufreq: intel_pstate: Add ->offline and ->online callbacks") Link: https://lore.kernel.org/linux-pm/adc7132c8655bd4d1c8b6129578e931a14fe1db2.camel@linux.intel.com/ Reported-by: Srinivas Pandruvada Cc: 5.9+ # 5.9+ Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Add Ice Lake server to out-of-band IDs

2021-11-23T13:02:10+00:00

Commit fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode") enabled the use of Intel P-State driver for Ice Lake servers. But it doesn't cover the case when OS can't control P-States. Therefore, for Ice Lake server, if MSR_MISC_PWR_MGMT bits 8 or 18 are enabled, then the Intel P-State driver should exit as OS can't control P-States. Fixes: fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode") Signed-off-by: Adamos Ttofari Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Clear HWP Status during HWP Interrupt enable

2021-11-04T18:48:47+00:00

It is possible that some performance excursions happened before OS boot or enable HWP interrupts. So clear MSR_HWP_STATUS bits when we enable HWP interrupt. In this way a next excursion will results in a HWP interrupt. The status bits of MSR_HWP_STATUS must be cleared (0) by software so that a new status condition change will cause the hardware to set the bit again and issue the notification. Fixes: 57577c996d73 ("cpufreq: intel_pstate: Process HWP Guaranteed change notification") Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Fix unchecked MSR 0x773 access

2021-11-04T18:48:47+00:00

It is possible that on some platforms HWP interrupts are disabled. In that case accessing MSR 0x773 will result in warning. So check X86_FEATURE_HWP_NOTIFY feature to access MSR 0x773. The other places in code where this MSR is accessed, already checks this feature except during disable path called during cpufreq offline and suspend callbacks. Fixes: 57577c996d73 ("cpufreq: intel_pstate: Process HWP Guaranteed change notification") Reported-by: Steven Rostedt Signed-off-by: Srinivas Pandruvada Tested-by: Steven Rostedt (VMware) Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Clear HWP desired on suspend/shutdown and offline

2021-11-04T18:48:47+00:00

Commit a365ab6b9dfb ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback") caused intel_pstate to use nonzero HWP desired values in certain usage scenarios, but it did not prevent them from being leaked into the confugirations in which HWP desired is expected to be 0. The failing scenarios are switching the driver from the passive mode to the active mode and starting a new kernel via kexec() while intel_pstate is running in the passive mode. To address this issue, ensure that HWP desired will be cleared on offline and suspend/shutdown. Fixes: a365ab6b9dfb ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback") Reported-by: Julia Lawall Tested-by: Julia Lawall Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Fix cpu->pstate.turbo_freq initialization

2021-10-26T14:00:50+00:00

Fix a problem in active mode that cpu->pstate.turbo_freq is initialized only if HWP-to-frequency scaling factor is refined. In passive mode, this problem is not exposed, because cpu->pstate.turbo_freq is set again, later in intel_cpufreq_cpu_init()->intel_pstate_get_hwp_cap(). Fixes: eb3693f0521e ("cpufreq: intel_pstate: hybrid: CPU-specific scaling factor") Signed-off-by: Zhang Rui Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Process HWP Guaranteed change notification

2021-10-05T13:30:44+00:00

It is possible that HWP guaranteed ratio is changed in response to change in power and thermal limits. For example when Intel Speed Select performance profile is changed or there is change in TDP, hardware can send notifications. It is possible that the guaranteed ratio is increased. This creates an issue when turbo is disabled, as the old limits set in MSR_HWP_REQUEST are still lower and hardware will clip to older limits. This change enables HWP interrupt and process HWP interrupts. When guaranteed is changed, calls cpufreq_update_policy() so that driver callbacks are called to update to new HWP limits. This callback is called from a delayed workqueue of 10ms to avoid frequent updates. Although the scope of IA32_HWP_INTERRUPT is per logical cpu, on some plaforms interrupt is generated on all CPUs. This is particularly a problem during initialization, when the driver didn't allocated data for other CPUs. So this change uses a cpumask of enabled CPUs and process interrupts on those CPUs only. When the cpufreq offline() or suspend() callback is called, HWP interrupt is disabled on those CPUs and also cancels any pending work item. Spin lock is used to protect data and processing shared with interrupt handler. Here READ_ONCE(), WRITE_ONCE() macros are used to designate shared data, even though spin lock act as an optimization barrier here. Signed-off-by: Srinivas Pandruvada Tested-by: pablomh@gmail.com Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Override parameters if HWP forced by BIOS

2021-09-13T17:26:08+00:00

If HWP has been already been enabled by BIOS, it may be necessary to override some kernel command line parameters. Once it has been enabled it requires a reset to be disabled. Suggested-by: Rafael J. Wysocki Signed-off-by: Doug Smythies Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: hybrid: Rework HWP calibration

2021-09-07T19:15:16+00:00

The current HWP calibration for hybrid processors in intel_pstate is fragile, because it depends too much on the information provided by the platform firmware via CPPC which may not be reliable enough. It also need not be so complicated. In order to improve that mechanism and make it more resistant to platform firmware issues, make it only use the CPPC nominal_perf values to compute the HWP-to-frequency scaling factors for all CPUs and possibly use the HWP_CAP highest_perf values to recompute them if the ones derived from the CPPC nominal_perf values alone appear to be too high. Namely, fetch CPC.nominal_perf for all CPUs present in the system, find the minimum one and use it as a reference for computing all of the CPUs' scaling factors (using the observation that for the CPUs having the minimum CPC.nominal_perf the HWP range of available performance levels should be the same as the range of available "legacy" P-states and so the HWP-to-frequency scaling factor for them should be the same as the corresponding scaling factor used for representing the P-state values in kHz). Signed-off-by: Rafael J. Wysocki Tested-by: Zhang Rui