From: Viresh Kumar <viresh.kumar@linaro.org>
To: Rafael Wysocki <rjw@rjwysocki.net>,
Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
Stephen Boyd <sboyd@codeaurora.org>
Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
jonathanh@nvidia.com, swarren@nvidia.com, treding@nvidia.com,
Viresh Kumar <viresh.kumar@linaro.org>
Subject: [PATCH] Revert "PM / OPP: Don't assume platform doesn't have regulators"
Date: Wed, 7 Dec 2016 16:01:52 +0530 [thread overview]
Message-ID: <1560e022c1584376cf5a55ed048e0b60485adf2b.1481106666.git.viresh.kumar@linaro.org> (raw)
This reverts commit ef3caabee9691386e6801ea92150e37277db9c7a.
The commit was based on the assumption that a platform with voltages
specified with individual OPPs, would have registered a regulator as
well in order to do full DVFS.
That assumption is broken by the Tegra124 platform.
For Tegra124, the voltage is not scaled via a direct call to the
regulator subsystem because the DFLL directly controls the I2C interface
that controls the voltage. The DFLL essentially figures out the max
frequency for a given voltage. So to run at a particular frequency, the
DFLL continuously adjusts the voltage in a control loop fashion to get
the desired frequency.
Following are the logs from: NVIDIA Tegra124 Jetson TK1
cpufreq: cpufreq_online: CPU0: Running at unlisted freq: 696000 KHz
cpu cpu0: dev_pm_opp_set_rate: Regulator not registered with OPP core
cpufreq: __target_index: Failed to change cpu frequency: -22
------------[ cut here ]------------
kernel BUG at drivers/cpufreq/cpufreq.c:1235!
Fix these by reverting the offending commit.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
Rafael, you can simply drop the patch if that is easier for you.
---
drivers/base/power/opp/core.c | 13 -------------
1 file changed, 13 deletions(-)
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 7db672f632d9..6af371a55062 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -747,20 +747,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
/* Only frequency scaling */
if (!regulators) {
- unsigned long u_volt = opp->supplies[0].u_volt;
-
rcu_read_unlock();
-
- /*
- * DT contained supply ratings? Consider platform failed to set
- * regulators.
- */
- if (unlikely(u_volt)) {
- dev_err(dev, "%s: Regulator not registered with OPP core\n",
- __func__);
- return -EINVAL;
- }
-
return _generic_set_opp_clk_only(dev, clk, old_freq, freq);
}
--
2.7.1.410.g6faf27b
next reply other threads:[~2016-12-07 10:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 10:31 Viresh Kumar [this message]
2016-12-07 23:29 ` [PATCH] Revert "PM / OPP: Don't assume platform doesn't have regulators" Rafael J. Wysocki
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