ba1edb9a51
The following warning was triggered after resumed from S3 - if all the nonboot CPUs were put offline before suspend: [ 1840.329515] unchecked MSR access error: RDMSR from 0x771 at rIP: 0xffffffff86061e3a (native_read_msr+0xa/0x30) [ 1840.329516] Call Trace: [ 1840.329521] __rdmsr_on_cpu+0x33/0x50 [ 1840.329525] generic_exec_single+0x81/0xb0 [ 1840.329527] smp_call_function_single+0xd2/0x100 [ 1840.329530] ? acpi_ds_result_pop+0xdd/0xf2 [ 1840.329532] ? acpi_ds_create_operand+0x215/0x23c [ 1840.329534] rdmsrl_on_cpu+0x57/0x80 [ 1840.329536] ? cpumask_next+0x1b/0x20 [ 1840.329538] ? rdmsrl_on_cpu+0x57/0x80 [ 1840.329541] intel_pstate_update_perf_limits+0xf3/0x220 [ 1840.329544] ? notifier_call_chain+0x4a/0x70 [ 1840.329546] intel_pstate_set_policy+0x4e/0x150 [ 1840.329548] cpufreq_set_policy+0xcd/0x2f0 [ 1840.329550] cpufreq_update_policy+0xb2/0x130 [ 1840.329552] ? cpufreq_update_policy+0x130/0x130 [ 1840.329556] acpi_processor_ppc_has_changed+0x65/0x80 [ 1840.329558] acpi_processor_notify+0x80/0x100 [ 1840.329561] acpi_ev_notify_dispatch+0x44/0x5c [ 1840.329563] acpi_os_execute_deferred+0x14/0x20 [ 1840.329565] process_one_work+0x193/0x3c0 [ 1840.329567] worker_thread+0x35/0x3b0 [ 1840.329569] kthread+0x125/0x140 [ 1840.329571] ? process_one_work+0x3c0/0x3c0 [ 1840.329572] ? kthread_park+0x60/0x60 [ 1840.329575] ? do_syscall_64+0x67/0x180 [ 1840.329577] ret_from_fork+0x25/0x30 [ 1840.329585] unchecked MSR access error: WRMSR to 0x774 (tried to write 0x0000000000000000) at rIP: 0xffffffff86061f78 (native_write_msr+0x8/0x30) [ 1840.329586] Call Trace: [ 1840.329587] __wrmsr_on_cpu+0x37/0x40 [ 1840.329589] generic_exec_single+0x81/0xb0 [ 1840.329592] smp_call_function_single+0xd2/0x100 [ 1840.329594] ? acpi_ds_create_operand+0x215/0x23c [ 1840.329595] ? cpumask_next+0x1b/0x20 [ 1840.329597] wrmsrl_on_cpu+0x57/0x70 [ 1840.329598] ? rdmsrl_on_cpu+0x57/0x80 [ 1840.329599] ? wrmsrl_on_cpu+0x57/0x70 [ 1840.329602] intel_pstate_hwp_set+0xd3/0x150 [ 1840.329604] intel_pstate_set_policy+0x119/0x150 [ 1840.329606] cpufreq_set_policy+0xcd/0x2f0 [ 1840.329607] cpufreq_update_policy+0xb2/0x130 [ 1840.329610] ? cpufreq_update_policy+0x130/0x130 [ 1840.329613] acpi_processor_ppc_has_changed+0x65/0x80 [ 1840.329615] acpi_processor_notify+0x80/0x100 [ 1840.329617] acpi_ev_notify_dispatch+0x44/0x5c [ 1840.329619] acpi_os_execute_deferred+0x14/0x20 [ 1840.329620] process_one_work+0x193/0x3c0 [ 1840.329622] worker_thread+0x35/0x3b0 [ 1840.329624] kthread+0x125/0x140 [ 1840.329625] ? process_one_work+0x3c0/0x3c0 [ 1840.329626] ? kthread_park+0x60/0x60 [ 1840.329628] ? do_syscall_64+0x67/0x180 [ 1840.329631] ret_from_fork+0x25/0x30 This is because if there's only one online CPU, the MSR_PM_ENABLE (package wide)can not be enabled after resumed, due to intel_pstate_hwp_enable() will only be invoked on AP's online process after resumed - if there's no AP online, the HWP remains disabled after resumed (BIOS has disabled it in S3). Then if there comes a _PPC change notification which touches HWP register during this stage, the warning is triggered. Since we don't call acpi_processor_register_performance() when HWP is enabled, the pr->performance will be NULL. When this is NULL we don't need to do _PPC change notification. Reported-by: Doug Smythies <dsmythies@telus.net> Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Yu Chen <yu.c.chen@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.