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    SubjectRe: [PATCH] opp: Fix dev_pm_opp_set_rate() to not return early
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    Quoting Rajendra Nayak (2020-08-10 00:06:19)
    > dev_pm_opp_set_rate() can now be called with freq = 0 inorder
    > to either drop performance or bandwidth votes or to disable
    > regulators on platforms which support them.
    > In such cases, a subsequent call to dev_pm_opp_set_rate() with
    > the same frequency ends up returning early because 'old_freq == freq'
    > Instead make it fall through and put back the dropped performance
    > and bandwidth votes and/or enable back the regulators.
    >
    > Fixes: cd7ea582 ("opp: Make dev_pm_opp_set_rate() handle freq = 0 to drop performance votes")
    > Reported-by: Sajida Bhanu <sbhanu@codeaurora.org>
    > Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
    > ---
    > drivers/opp/core.c | 8 +++++++-
    > 1 file changed, 7 insertions(+), 1 deletion(-)
    >
    > diff --git a/drivers/opp/core.c b/drivers/opp/core.c
    > index 0c8c74a..a994f30 100644
    > --- a/drivers/opp/core.c
    > +++ b/drivers/opp/core.c
    > @@ -901,6 +901,9 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
    >
    > /* Return early if nothing to do */
    > if (old_freq == freq) {
    > + if (opp_table->required_opp_tables || opp_table->regulators ||
    > + opp_table->paths)
    > + goto skip_clk_only;

    This is a goto maze! Any chance we can clean this up?

    if (!opp_table->required_opp_tables && !opp_table->regulators &&
    !opp_table->paths)
    if (old_freq == freq) {
    ret = 0
    dev_dbg(..)
    } else if (!_get_opp_count(opp_table)) {
    ret = _generic_set_opp_clk_only(dev, clk, freq);
    }
    } else {
    temp_freq = old_freq;
    old_opp = _find_freq_ceil(opp_table, &temp_freq);
    ...
    dev_pm_opp_put(opp);
    put_old_opp:
    if (!IS_ERR(old_opp))
    dev_pm_opp_put(old_opp);
    }
    put_opp_table:
    dev_pm_opp_put_opp_table(opp_table);

    And that stuff in the else should probably go to another function.

    > dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
    > __func__, freq);
    > ret = 0;
    > @@ -919,6 +922,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
    > goto put_opp_table;
    > }
    >
    > +skip_clk_only:
    > temp_freq = old_freq;
    > old_opp = _find_freq_ceil(opp_table, &temp_freq);
    > if (IS_ERR(old_opp)) {
    > @@ -954,8 +958,10 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
    > IS_ERR(old_opp) ? NULL : old_opp->supplies,
    > opp->supplies);
    > } else {
    > + ret = 0;
    > /* Only frequency scaling */
    > - ret = _generic_set_opp_clk_only(dev, clk, freq);
    > + if (freq != old_freq)
    > + ret = _generic_set_opp_clk_only(dev, clk, freq);
    > }

    And write this as

    else if (freq != old_freq) {
    ret = _generic_set_opp_clk_only(..)
    } else {
    ret = 0;
    }

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