linux-kernel - [PATCH] PM / OPP: Remove confusing error message in of_cpumask_init_opp

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Date:	Wed, 14 Oct 2015 17:52:23 +0200
From:	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
To:	Viresh Kumar <viresh.kumar@...aro.org>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Tawfik Bayouk <tawfik@...vell.com>,
	Nadav Haklai <nadavh@...vell.com>,
	Lior Amsalem <alior@...vell.com>,
	Gregory Clement <gregory.clement@...e-electrons.com>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
Subject: [PATCH] PM / OPP: Remove confusing error message in of_cpumask_init_opp_table()

The of_cpumask_init_opp_table() function will print an error message
(with pr_err) if it cannot find the OPP table for a certain CPU in the
Device Tree.

There are users of the cpufreq-dt driver (which is the one calling
of_cpumask_init_opp_table) that do not have the OPP points defined in
the Device Tree. Instead, such users dynamically create the OPP table
at boot time depending on the system configuration. Such a case is
planned in the cpufreq-dt driver, which on purpose ignores the return
value of of_cpumask_init_opp_table() with the following comment: "OPPs
might be populated at runtime, don't check for error here".

For such platforms, the of_cpumask_init_opp_table() prints a spurious
and confusing error message for each CPU:

[    1.749548] of_cpumask_init_opp_table: couldn't find opp table for cpu:0, -19
[    1.756784] of_cpumask_init_opp_table: couldn't find opp table for cpu:1, -19
[    1.764031] of_cpumask_init_opp_table: couldn't find opp table for cpu:2, -19
[    1.771268] of_cpumask_init_opp_table: couldn't find opp table for cpu:3, -19

This is confusing because everything is working fine, cpufreq works
and it knows the OPP table that was registered at boot time (on
Marvell Armada XP):

$ cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state
666500 1884
1333000 23333

To avoid this confusion, this patch simply deletes the error message.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
---
 drivers/base/power/opp.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 7ae7cd9..11206d2 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -1489,9 +1489,6 @@ int of_cpumask_init_opp_table(cpumask_var_t cpumask)
 
 		ret = of_init_opp_table(cpu_dev);
 		if (ret) {
-			pr_err("%s: couldn't find opp table for cpu:%d, %d\n",
-			       __func__, cpu, ret);
-
 			/* Free all other OPPs */
 			of_cpumask_free_opp_table(cpumask);
 			break;
-- 
2.6.1

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