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author | Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> | 2014-02-17 16:18:21 +0530 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-03-06 22:06:22 -0800 |
commit | c6c54cb0037e20c772ccc5c0e3b0506e402789f8 (patch) | |
tree | 0e2b591ebcc86f37bfc83fe5e88fab6c5bea1a0e /fs/fs-writeback.c | |
parent | 2263f03bcb38ae553fabf83150011643dad3359f (diff) | |
download | lwn-c6c54cb0037e20c772ccc5c0e3b0506e402789f8.tar.gz lwn-c6c54cb0037e20c772ccc5c0e3b0506e402789f8.zip |
cpufreq: powernow-k8: Initialize per-cpu data-structures properly
commit c3274763bfc3bf1ececa269ed6e6c4d7ec1c3e5e upstream.
The powernow-k8 driver maintains a per-cpu data-structure called
powernow_data that is used to perform the frequency transitions.
It initializes this data structure only for the policy->cpu. So,
accesses to this data structure by other CPUs results in various
problems because they would have been uninitialized.
Specifically, if a cpu (!= policy->cpu) invokes the drivers' ->get()
function, it returns 0 as the KHz value, since its per-cpu memory
doesn't point to anything valid. This causes problems during
suspend/resume since cpufreq_update_policy() tries to enforce this
(0 KHz) as the current frequency of the CPU, and this madness gets
propagated to adjust_jiffies() as well. Eventually, lots of things
start breaking down, including the r8169 ethernet card, in one
particularly interesting case reported by Pierre Ossman.
Fix this by initializing the per-cpu data-structures of all the CPUs
in the policy appropriately.
References: https://bugzilla.kernel.org/show_bug.cgi?id=70311
Reported-by: Pierre Ossman <pierre@ossman.eu>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/fs-writeback.c')
0 files changed, 0 insertions, 0 deletions