[PATCH] opp: Fix dev_pm_opp_set_rate() to not return early

From: Rajendra Nayak
Date: Mon Aug 10 2020 - 03:08:32 EST


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@xxxxxxxxxxxxxx>
Signed-off-by: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>
---
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;
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);
}

/* Scaling down? Configure required OPPs after frequency */
--
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