lkml.org 
[lkml]   [2023]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    SubjectRe: [PATCH v1 1/4] ACPI: processor: Reorder acpi_processor_driver_init()
    Date
    On Fri, 2023-03-03 at 20:19 +0100, Rafael J. Wysocki wrote:
    > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    >
    > The cpufreq policy notifier in the ACPI processor driver may as
    > well be registered before the driver itself, which causes
    > acpi_processor_cpufreq_init to be true (unless the notifier
    > registration fails, which is unlikely at that point) when the
    > ACPI CPU thermal cooling devices are registered, so the
    > processor_get_max_state() result does not change while
    > acpi_processor_driver_init() is running.
    >
    > Change the ordering in acpi_processor_driver_init() accordingly
    > to prevent the max_state value from remaining 0 permanently for all
    > ACPI CPU cooling devices.
    >
    > Fixes: a365105c685c("thermal: sysfs: Reuse cdev->max_state")
    > Reported-by: Wang, Quanxian <quanxian.wang@intel.com>
    > Link:
    > https://lore.kernel.org/linux-pm/53ec1f06f61c984100868926f282647e57ecfb2d.camel@intel.com/
    > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

    The full patch series fixes the problem but this one does not.

    This is because,

    static int cpu_has_cpufreq(unsigned int cpu)
    {
    struct
    cpufreq_policy *policy;

    if (!acpi_processor_cpufreq_init)
    return 0;

    policy = cpufreq_cpu_get(cpu);
    if (policy) {
    cpufreq_cpu_put(policy);
    return 1;
    }
    return 0;
    }

    Although acpi_processor_cpufreq_init is set to true with patch 1/4, but
    we don't have cpufreq driver registered, thus cpufreq_cpu_get() return
    NULL.

    so acpi_processor_cpufreq_init is not the only dependency here. :(

    thanks,
    rui

    > ---
    > drivers/acpi/processor_driver.c | 12 ++++++------
    > 1 file changed, 6 insertions(+), 6 deletions(-)
    >
    > Index: linux-pm/drivers/acpi/processor_driver.c
    > ===================================================================
    > --- linux-pm.orig/drivers/acpi/processor_driver.c
    > +++ linux-pm/drivers/acpi/processor_driver.c
    > @@ -263,6 +263,12 @@ static int __init acpi_processor_driver_
    > if (acpi_disabled)
    > return 0;
    >
    > + if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
    > + CPUFREQ_POLICY_NOTIFIER)) {
    > + acpi_processor_cpufreq_init = true;
    > + acpi_processor_ignore_ppc_init();
    > + }
    > +
    > result = driver_register(&acpi_processor_driver);
    > if (result < 0)
    > return result;
    > @@ -276,12 +282,6 @@ static int __init acpi_processor_driver_
    > cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-
    > drv:dead",
    > NULL, acpi_soft_cpu_dead);
    >
    > - if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
    > - CPUFREQ_POLICY_NOTIFIER)) {
    > - acpi_processor_cpufreq_init = true;
    > - acpi_processor_ignore_ppc_init();
    > - }
    > -
    > acpi_processor_throttling_init();
    > return 0;
    > err:
    >
    >
    >
    \
     
     \ /
      Last update: 2023-03-27 00:55    [W:6.442 / U:0.120 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site