linux-kernel - [PATCH 5.8 022/148] opp: Enable resources again if they were disabled earlier

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Date:   Mon, 24 Aug 2020 10:28:40 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sajida Bhanu <sbhanu@...eaurora.org>,
        Sibi Sankar <sibis@...eaurora.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH 5.8 022/148] opp: Enable resources again if they were disabled earlier

From: Rajendra Nayak <rnayak@...eaurora.org>

commit a4501bac0e553bed117b7e1b166d49731caf7260 upstream.

dev_pm_opp_set_rate() can now be called with freq = 0 in order
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.

Cc: v5.3+ <stable@...r.kernel.org> # v5.3+
Fixes: cd7ea582866f ("opp: Make dev_pm_opp_set_rate() handle freq = 0 to drop performance votes")
Reported-by: Sajida Bhanu <sbhanu@...eaurora.org>
Reviewed-by: Sibi Sankar <sibis@...eaurora.org>
Reported-by: Matthias Kaehlcke <mka@...omium.org>
Tested-by: Matthias Kaehlcke <mka@...omium.org>
Reviewed-by: Stephen Boyd <sboyd@...nel.org>
Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
[ Viresh: Don't skip clk_set_rate() and massaged changelog ]
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/opp/core.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -901,10 +901,13 @@ int dev_pm_opp_set_rate(struct device *d
 
 	/* Return early if nothing to do */
 	if (old_freq == freq) {
-		dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
-			__func__, freq);
-		ret = 0;
-		goto put_opp_table;
+		if (!opp_table->required_opp_tables && !opp_table->regulators &&
+		    !opp_table->paths) {
+			dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
+				__func__, freq);
+			ret = 0;
+			goto put_opp_table;
+		}
 	}
 
 	/*