On 12/07/17 14:59, Ulf Hansson wrote: > On 29 June 2017 at 20:00, Sudeep Holla <sudeep.ho...@arm.com> 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. > > Right, this makes sense. >
Thanks >> >> Cc: "Rafael J. Wysocki" <r...@rjwysocki.net> >> Cc: Kevin Hilman <khil...@kernel.org> >> Cc: Ulf Hansson <ulf.hans...@linaro.org> >> Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com> > > Could we perhaps work out which commit it fixes, or perhaps the > problem been there long time ago and we should just add a stable tag? > OK I will dig that out. >> --- >> drivers/base/power/domain.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >> index da49a8383dc3..b195d34de888 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: >> @@ -1221,6 +1219,8 @@ 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; >> >> -- >> 2.7.4 >> > > One piece is missing to make this fix complete. > > More precisely, you must also move the call to dev_pm_domain_set(dev, NULL). > Sure will add. > Currently that is done from genpd_free_dev_data(), as it corresponds > to genpd_alloc_dev_data(), but clearly the proper place to call it > should be from genpd_remove_device(). > OK, will also look into that. -- Regards, Sudeep
