* [PATCH] Revert "PM / OPP: Don't assume platform doesn't have regulators"
@ 2016-12-07 10:31 Viresh Kumar
2016-12-07 23:29 ` Rafael J. Wysocki
0 siblings, 1 reply; 2+ messages in thread
From: Viresh Kumar @ 2016-12-07 10:31 UTC (permalink / raw)
To: Rafael Wysocki, Viresh Kumar, Nishanth Menon, Stephen Boyd
Cc: linaro-kernel, linux-pm, linux-kernel, Vincent Guittot,
jonathanh, swarren, treding, Viresh Kumar
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] Revert "PM / OPP: Don't assume platform doesn't have regulators"
2016-12-07 10:31 [PATCH] Revert "PM / OPP: Don't assume platform doesn't have regulators" Viresh Kumar
@ 2016-12-07 23:29 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2016-12-07 23:29 UTC (permalink / raw)
To: Viresh Kumar
Cc: Rafael Wysocki, Viresh Kumar, Nishanth Menon, Stephen Boyd,
Lists linaro-kernel, Linux PM, Linux Kernel Mailing List,
Vincent Guittot, Jon Hunter, swarren, Thierry Reding
On Wed, Dec 7, 2016 at 11:31 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> 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.
Done.
Thanks,
Rafael
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