From: "N. Coesel" <nico@nctdev.nl>
To: linux-kernel@vger.kernel.org
Subject: Cpufreq shutdown patch (kernel 2.6.35.3)
Date: Thu, 19 Jan 2012 22:18:10 +0100 [thread overview]
Message-ID: <CPSMTPM-CMT109lZGdO0011ecc5@CPSMTPM-CMT109.kpnxchange.com> (raw)
Dear readers,
I've found a problem in drivers/cpufreq/cpufreq.c. The driver does
not execute the exit member of the low level driver when shutting
down for a reboot (reset). This potentially leaves the power supply
at a too low voltage to boot the system properly. The patch below
adds a shutdown function which executes the exit member of the low
level driver which allows a system to be properly prepared for a reset.
--- drivers/cpufreq/cpufreq.c.orig 2010-08-20 20:55:55.000000000 +0200
+++ drivers/cpufreq/cpufreq.c 2012-01-19 21:50:46.000000000 +0100
@@ -1431,11 +1431,34 @@ fail:
return ret;
}
+
+static int cpufreq_shutdown(struct sys_device *sysdev)
+{
+ struct cpufreq_policy *cpu_policy;
+ int cpu = sysdev->id;
+ int ret =0;
+
+ if (!cpu_online(cpu))
+ return 0;
+
+ cpu_policy = cpufreq_cpu_get(cpu);
+ if (!cpu_policy)
+ return -EINVAL;
+
+// printk("cpufreq_shutdown %d \n", cpu);
+ if (cpufreq_driver->exit)
+ ret = cpufreq_driver->exit(cpu_policy);
+
+ return ret;
+}
+
+
static struct sysdev_driver cpufreq_sysdev_driver = {
.add = cpufreq_add_dev,
.remove = cpufreq_remove_dev,
.suspend = cpufreq_suspend,
.resume = cpufreq_resume,
+ .shutdown = cpufreq_shutdown,
};
Signed of by: Nico Coesel nico@nctdev.nl
next reply other threads:[~2012-01-19 21:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-19 21:18 N. Coesel [this message]
2012-02-13 16:28 ` Cpufreq shutdown patch (kernel 2.6.35.3) Dave Jones
2012-02-13 16:35 ` Dave Jones
2012-02-14 14:03 ` Kay Sievers
2012-02-13 16:45 ` N. Coesel
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