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    SubjectRe: [PATCH v2 1/4] OPP: Allow required-opps even if the device doesn't have power-domains
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    Hey Saravana,
    Thanks for taking time to post out this series.

    On 6/26/19 3:03 AM, Saravana Kannan wrote:
    > A Device-A can have a (minimum) performance requirement on another
    > Device-B to be able to function correctly. This performance requirement
    > on Device-B can also change based on the current performance level of
    > Device-A.
    >
    > The existing required-opps feature fits well to describe this need. So,
    > instead of limiting required-opps to point to only PM-domain devices,
    > allow it to point to any device.
    >
    > Signed-off-by: Saravana Kannan <saravanak@google.com>
    > ---
    > drivers/opp/core.c | 2 +-
    > drivers/opp/of.c | 14 --------------
    > 2 files changed, 1 insertion(+), 15 deletions(-)
    >
    > diff --git a/drivers/opp/core.c b/drivers/opp/core.c
    > index 0e7703fe733f..74c7bdc6f463 100644
    > --- a/drivers/opp/core.c
    > +++ b/drivers/opp/core.c
    > @@ -710,7 +710,7 @@ static int _set_required_opps(struct device *dev,
    > return 0;
    >
    > /* Single genpd case */
    > - if (!genpd_virt_devs) {
    > + if (!genpd_virt_devs && required_opp_tables[0]->is_genpd) {

    https://patchwork.kernel.org/patch/10940671/
    This was already removed as a part of ^^ and is in linux-next.

    > pstate = opp->required_opps[0]->pstate;
    > ret = dev_pm_genpd_set_performance_state(dev, pstate);
    > if (ret) {
    > diff --git a/drivers/opp/of.c b/drivers/opp/of.c
    > index c10c782d15aa..7c8336e94aff 100644
    > --- a/drivers/opp/of.c
    > +++ b/drivers/opp/of.c
    > @@ -195,9 +195,6 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
    > */
    > count_pd = of_count_phandle_with_args(dev->of_node, "power-domains",
    > "#power-domain-cells");
    > - if (!count_pd)
    > - goto put_np;
    > -
    > if (count_pd > 1) {
    > genpd_virt_devs = kcalloc(count, sizeof(*genpd_virt_devs),
    > GFP_KERNEL);
    > @@ -226,17 +223,6 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
    >
    > if (IS_ERR(required_opp_tables[i]))
    > goto free_required_tables;
    > -
    > - /*
    > - * We only support genpd's OPPs in the "required-opps" for now,
    > - * as we don't know how much about other cases. Error out if the
    > - * required OPP doesn't belong to a genpd.
    > - */
    > - if (!required_opp_tables[i]->is_genpd) {
    > - dev_err(dev, "required-opp doesn't belong to genpd: %pOF\n",
    > - required_np);
    > - goto free_required_tables;
    > - }

    I expect the series to not work as is in its current state since I
    see a circular dependency here. The required-opp tables of the parent
    devfreq won't be populated until we add the opp-table of the child
    devfreq node while the child devfreq using passive governor would
    return -EPROBE_DEFER until the parent devfreq probes.

    The same applies to this patch -> https://patchwork.kernel.org/patch
    /11046147/ I posted out based on your series. So we would probably have
    to address the dependency here.

    > }
    >
    > goto put_np;
    >

    --
    Qualcomm Innovation Center, Inc.
    Qualcomm Innovation Center, Inc, is a member of Code Aurora Forum,
    a Linux Foundation Collaborative Project

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