linux-stable.git/drivers/cpufreq, branch v3.15.7

cpufreq: move policy kobj to policy->cpu at resume

2014-07-28T15:08:27+00:00

commit 92c14bd9477a20a83144f08c0ca25b0308bf0730 upstream.

This is only relevant to implementations with multiple clusters, where clusters
have separate clock lines but all CPUs within a cluster share it.

Consider a dual cluster platform with 2 cores per cluster. During suspend we
start hot unplugging CPUs in order 1 to 3. When CPU2 is removed, policy->kobj
would be moved to CPU3 and when CPU3 goes down we wouldn't free policy or its
kobj as we want to retain permissions/values/etc.

Now on resume, we will get CPU2 before CPU3 and will call __cpufreq_add_dev().
We will recover the old policy and update policy->cpu from 3 to 2 from
update_policy_cpu().

But the kobj is still tied to CPU3 and isn't moved to CPU2. We wouldn't create a
link for CPU2, but would try that for CPU3 while bringing it online. Which will
report errors as CPU3 already has kobj assigned to it.

This bug got introduced with commit 42f921a, which overlooked this scenario.

To fix this, lets move kobj to the new policy->cpu while bringing first CPU of a
cluster back. Also do a WARN_ON() if kobject_move failed, as we would reach here
only for the first CPU of a non-boot cluster. And we can't recover from this
situation, if kobject_move() fails.

Fixes: 42f921a6f10c (cpufreq: remove sysfs files for CPUs which failed to come back after resume)
Reported-and-tested-by: Bu Yitian
Reported-by: Saravana Kannan
Reviewed-by: Srivatsa S. Bhat
Signed-off-by: Viresh Kumar
Signed-off-by: Rafael J. Wysocki
Signed-off-by: Greg Kroah-Hartman

intel_pstate: Set CPU number before accessing MSRs

2014-07-17T23:23:15+00:00

commit 179e8471673ce0249cd4ecda796008f7757e5bad upstream.

Ensure that cpu->cpu is set before writing MSR_IA32_PERF_CTL during CPU
initialization. Otherwise only cpu0 has its P-state set and all other
cores are left with their values unchanged.

In most cases, this is not too serious because the P-states will be set
correctly when the timer function is run.  But when the default governor
is set to performance, the per-CPU current_pstate stays the same forever
and no attempts are made to write the MSRs again.

Signed-off-by: Vincent Minet 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

intel_pstate: don't touch turbo bit if turbo disabled or unavailable.

2014-07-17T23:23:15+00:00

commit dd5fbf70f96dbfd7ee432096a1f979b2b3267856 upstream.

If turbo is disabled in the BIOS bit 38 should be set in
MSR_IA32_MISC_ENABLE register per section 14.3.2.1 of the SDM Vol 3
document 325384-050US Feb 2014.  If this bit is set do *not* attempt
to disable trubo via the MSR_IA32_PERF_CTL register.  On some systems
trying to disable turbo via MSR_IA32_PERF_CTL will cause subsequent
writes to MSR_IA32_PERF_CTL not take affect, in fact reading
MSR_IA32_PERF_CTL will not show the IDA/Turbo DISENGAGE bit(32) as
set. A write of bit 32 to zero returns to normal operation.

Also deal with the case where the processor does not support
turbo and the BIOS does not report the fact in MSR_IA32_MISC_ENABLE
but does report the max and turbo P states as the same value.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=64251
Signed-off-by: Dirk Brandewie 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

intel_pstate: Fix setting VID

2014-07-17T23:23:14+00:00

commit c16ed06024a6e699c332831dd50d8276744e3de8 upstream.

Commit 21855ff5 (intel_pstate: Set turbo VID for BayTrail) introduced
setting the turbo VID which is required to prevent a machine check on
some Baytrail SKUs under heavy graphics based workloads.  The
docmumentation update that brought the requirement to light also
changed the bit mask used for enumerating P state and VID values from
0x7f to 0x3f.

This change returns the mask value to 0x7f.

Tested with the Intel NUC DN2820FYK,
BIOS version FYBYT10H.86A.0034.2014.0513.1413 with v3.16-rc1 and
v3.14.8 kernel versions.

Fixes: 21855ff5 (intel_pstate: Set turbo VID for BayTrail)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77951
Reported-and-tested-by: Rune Reterson 
Reported-and-tested-by: Eric Eickmeyer 
Signed-off-by: Dirk Brandewie 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: Makefile: fix compilation for davinci platform

2014-07-17T23:23:13+00:00

commit 5a90af67c2126fe1d04ebccc1f8177e6ca70d3a9 upstream.

Since commtit 8a7b1227e303 (cpufreq: davinci: move cpufreq driver to
drivers/cpufreq) this added dependancy only for CONFIG_ARCH_DAVINCI_DA850
where as davinci_cpufreq_init() call is used by all davinci platform.

This patch fixes following build error:

arch/arm/mach-davinci/built-in.o: In function `davinci_init_late':
:(.init.text+0x928): undefined reference to `davinci_cpufreq_init'
make: *** [vmlinux] Error 1

Fixes: 8a7b1227e303 (cpufreq: davinci: move cpufreq driver to drivers/cpufreq)
Signed-off-by: Lad, Prabhakar 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

intel_pstate: Correct rounding in busy calculation

2014-07-09T18:21:28+00:00

commit 51d211e9c334b9eca3505f4052afa660c3e0606b upstream.

There was a mistake in the actual rounding portion this previous patch:
f0fe3cd7e12d (intel_pstate: Correct rounding in busy calculation) such that
the rounding was asymetric and incorrect.

Severity: Not very serious, but can increase target pstate by one extra value.
For real world work flows the issue should self correct (but I have no proof).
It is the equivalent of different PID gains for positive and negative numbers.

Examples:
 -3.000000 used to round to -4, rounds to -3 with this patch.
 -3.503906 used to round to -5, rounds to -4 with this patch.

Fixes: f0fe3cd7e12d (intel_pstate: Correct rounding in busy calculation)
Signed-off-by: Doug Smythies 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: unlock when failing cpufreq_update_policy()

2014-07-07T01:59:12+00:00

commit fefa8ff810c5ab4c4206aed9d159c4d6fe8d4f1c upstream.

Commit bd0fa9bb455d introduced a failure path to cpufreq_update_policy() if
cpufreq_driver->get(cpu) returns NULL.  However, it jumps to the 'no_policy'
label, which exits without unlocking any of the locks the function acquired
earlier.  This causes later calls into cpufreq to hang.

Fix this by creating a new 'unlock' label and jumping to that instead.

Fixes: bd0fa9bb455d ("cpufreq: Return error if ->get() failed in cpufreq_update_policy()")
Link: https://devtalk.nvidia.com/default/topic/751903/kernel-3-15-and-nv-drivers-337-340-failed-to-initialize-the-nvidia-kernel-module-gtx-550-ti-/
Signed-off-by: Aaron Plattner 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: ppc-corenet-cpu-freq: do_div use quotient

2014-07-07T01:59:12+00:00

commit 906fe033145aab7d65a428bfda2cf19c75720894 upstream.

Commit 6712d2931933 (cpufreq: ppc-corenet-cpufreq: Fix __udivdi3 modpost
error) used the remainder from do_div instead of the quotient.  Fix that
and add one to ensure minimum is met.

Fixes: 6712d2931933 (cpufreq: ppc-corenet-cpufreq: Fix __udivdi3 modpost error)
Signed-off-by: Ed Swarthout 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

intel_pstate: Improve initial busy calculation

2014-06-02T10:46:01+00:00

This change makes the busy calculation using 64 bit math which prevents
overflow for large values of aperf/mperf.

Cc: 3.14+  # 3.14+
Signed-off-by: Doug Smythies 
Signed-off-by: Dirk Brandewie 
Signed-off-by: Rafael J. Wysocki

intel_pstate: add sample time scaling

2014-06-02T10:45:05+00:00

The PID assumes that samples are of equal time, which for a deferable
timers this is not true when the system goes idle.  This causes the
PID to take a long time to converge to the min P state and depending
on the pattern of the idle load can make the P state appear stuck.

The hold-off value of three sample times before using the scaling is
to give a grace period for applications that have high performance
requirements and spend a lot of time idle,  The poster child for this
behavior is the ffmpeg benchmark in the Phoronix test suite.

Cc: 3.14+  # 3.14+
Signed-off-by: Dirk Brandewie 
Signed-off-by: Rafael J. Wysocki