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    Subject[PATCH 4.12 190/196] PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present
    Date
    4.12-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Sudeep Holla <Sudeep.Holla@arm.com>

    commit 975e83cfb8dc16e7a2fdc58188c77c0c605876c2 upstream.

    If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach
    may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets
    the PM domain for the device unconditionally.

    When subsequent attempts are made to call genpd_dev_pm_attach, it may
    return -EEXISTS checking dev->pm_domain without re-attempting to call
    attach_dev or power_on.

    platform_drv_probe then attempts to call drv->probe as the return value
    -EEXIST != -EPROBE_DEFER, which may end up in a situation where the
    device is accessed without it's power domain switched on.

    Fixes: f104e1e5ef57 (PM / Domains: Re-order initialization of generic_pm_domain_data)
    Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
    Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/base/power/domain.c | 8 ++++----
    1 file changed, 4 insertions(+), 4 deletions(-)

    --- a/drivers/base/power/domain.c
    +++ b/drivers/base/power/domain.c
    @@ -1168,8 +1168,6 @@ static struct generic_pm_domain_data *ge

    spin_unlock_irq(&dev->power.lock);

    - dev_pm_domain_set(dev, &genpd->domain);
    -
    return gpd_data;

    err_free:
    @@ -1183,8 +1181,6 @@ static struct generic_pm_domain_data *ge
    static void genpd_free_dev_data(struct device *dev,
    struct generic_pm_domain_data *gpd_data)
    {
    - dev_pm_domain_set(dev, NULL);
    -
    spin_lock_irq(&dev->power.lock);

    dev->power.subsys_data->domain_data = NULL;
    @@ -1221,6 +1217,8 @@ static int genpd_add_device(struct gener
    if (ret)
    goto out;

    + dev_pm_domain_set(dev, &genpd->domain);
    +
    genpd->device_count++;
    genpd->max_off_time_changed = true;

    @@ -1282,6 +1280,8 @@ static int genpd_remove_device(struct ge
    if (genpd->detach_dev)
    genpd->detach_dev(genpd, dev);

    + dev_pm_domain_set(dev, NULL);
    +
    list_del_init(&pdd->list_node);

    genpd_unlock(genpd);

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