On Friday, July 14, 2017 11:51:48 AM Sudeep Holla wrote:
> 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")
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> Cc: Kevin Hilman <khilman@xxxxxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.0+
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Ulf, Kevin?
> ---
> drivers/base/power/domain.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> Hi,
>
> I have added Cc/Fixes tags based on the original commit that caused the issue.
> I need to workout a patch that can cleanly apply before commit 989561de9b51
> ("PM / Domains: add setter for dev.pm_domain"), i.e. for v4.0.x to v4.4.x
> This patch should apply from v4.5.x onwards.
>
> Let me know if I got anything wrong.
>
> v1->v2: Moved dev_pm_domain_set(dev, NULL) from genpd_free_dev_data
>
> Regards,
> Sudeep
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index da49a8383dc3..2d9178660061 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1168,8 +1168,6 @@ static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
>
> 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 *genpd_alloc_dev_data(struct device *dev,
> 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 generic_pm_domain *genpd, struct device *dev,
> 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 generic_pm_domain *genpd,
> if (genpd->detach_dev)
> genpd->detach_dev(genpd, dev);
>
> + dev_pm_domain_set(dev, NULL);
> +
> list_del_init(&pdd->list_node);
>
> genpd_unlock(genpd);
>