In the current code, if we fail during a frequency transition, we
simply send the POSTCHANGE notification with the old frequency. This
isn't enough.
One of the core users of these notifications is the code responsible
for keeping loops_per_jiffy aligned with frequency changes. And mostly
it is written as:
if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
(val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
update-loops-per-jiffy...
}
So, suppose we are changing to a higher frequency and failed during
transition, then following will happen:
- CPUFREQ_PRECHANGE notification with freq-new > freq-old
- CPUFREQ_POSTCHANGE notification with freq-new == freq-old
The first one will update loops_per_jiffy and second one will do
nothing. Even if we send the 2nd notification by exchanging values of
freq-new and old, some users of these notifications might get
unstable.
This can be fixed by simply calling cpufreq_notify_post_transition()
with error code and this routine will take care of sending
notifications in the correct order.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[rjw: Folded 3 patches into one, rebased unicore2 changes]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* pm-cpufreq: (167 commits)
cpufreq: create per policy rwsem instead of per CPU cpu_policy_rwsem
intel_pstate: Add Baytrail support
intel_pstate: Refactor driver to support CPUs with different MSR layouts
cpufreq: Implement light weight ->target_index() routine
PM / OPP: rename header to linux/pm_opp.h
PM / OPP: rename data structures to dev_pm equivalents
PM / OPP: rename functions to dev_pm_opp*
cpufreq / governor: Remove fossil comment
cpufreq: exynos4210: Use the common clock framework to set APLL clock rate
cpufreq: exynos4x12: Use the common clock framework to set APLL clock rate
cpufreq: Detect spurious invocations of update_policy_cpu()
cpufreq: pmac64: enable cpufreq on iMac G5 (iSight) model
cpufreq: pmac64: provide cpufreq transition latency for older G5 models
cpufreq: pmac64: speed up frequency switch
cpufreq: highbank-cpufreq: Enable Midway/ECX-2000
exynos-cpufreq: fix false return check from "regulator_set_voltage"
speedstep-centrino: Remove unnecessary braces
acpi-cpufreq: Add comment under ACPI_ADR_SPACE_SYSTEM_IO case
cpufreq: arm-big-little: use clk_get instead of clk_get_sys
cpufreq: exynos: Show a list of available frequencies
...
Conflicts:
drivers/devfreq/exynos/exynos5_bus.c
Many common initializations of struct policy are moved to core now and hence
this driver doesn't need to do it. This patch removes such code.
Most recent of those changes is to call ->get() in the core after calling
->init().
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Most of the users of cpufreq_verify_within_limits() calls it for
limiting with min/max from policy->cpuinfo. We can make that code
simple by introducing another routine which will do this for them
automatically.
This patch adds another routine cpufreq_verify_within_cpu_limits()
and updates others to use it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
acpi_has_method() is a new ACPI API introduced to check
the existence of an ACPI control method.
It can be used to replace acpi_get_handle() in the case that
1. the calling function doesn't need the ACPI handle of the control method.
and
2. the calling function doesn't care the reason why the method is unavailable.
Convert acpi_get_handle() to acpi_has_method()
in drivers/cpufreq/pcc_freq.c in this patch.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We don't need to set .owner = THIS_MODULE any more in cpufreq drivers
as this field isn't used any more by the cpufreq core.
This patch removes it and updates all dependent drivers accordingly.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e
either both should be called or both shouldn't be.
In case we have started PRECHANGE notifier and found an error, we
must call POSTCHANGE notifier with freqs.new = freqs.old to guarantee
that the sequence of calling notifiers is complete.
This patch fixes it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
policy->cpus contains all online cpus that have single shared clock line. And
their frequencies are always updated together.
Many SMP system's cpufreq drivers take care of this in individual drivers but
the best place for this code is in cpufreq core.
This patch modifies cpufreq_notify_transition() to notify frequency change for
all cpus in policy->cpus and hence updates all users of this API.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Convert a 0 error return code to a negative one, as returned elsewhere in the
function.
A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@
(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
when != ret = e3
*if (x == NULL || ...)
{
... when != ret = e4
* return ret;
}
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
per_cpu(processors, n) can be NULL, resulting in:
Loading CPUFreq modules[ 437.661360] BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa0434314>] pcc_cpufreq_cpu_init+0x74/0x220 [pcc_cpufreq]
It's better to avoid the oops by failing the driver, and allowing the
system to boot.
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
