path: root/drivers/cpufreq/powernow-k8.c
diff options
authorSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>2014-02-17 16:18:21 +0530
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-02-19 01:04:56 +0100
commitc3274763bfc3bf1ececa269ed6e6c4d7ec1c3e5e (patch)
tree849fe849d4b6bde9c2aecd5c31ee519beff6c431 /drivers/cpufreq/powernow-k8.c
parent6964d91db2becfe80658f50584d264708ca7f49e (diff)
cpufreq: powernow-k8: Initialize per-cpu data-structures properly
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> Cc: All applicable <stable@vger.kernel.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/powernow-k8.c')
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index e10b646634d7..6684e0342792 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1076,7 +1076,7 @@ static int powernowk8_cpu_init(struct cpufreq_policy *pol)
struct powernow_k8_data *data;
struct init_on_cpu init_on_cpu;
- int rc;
+ int rc, cpu;
smp_call_function_single(pol->cpu, check_supported_cpu, &rc, 1);
if (rc)
@@ -1140,7 +1140,9 @@ static int powernowk8_cpu_init(struct cpufreq_policy *pol)
pr_debug("cpu_init done, current fid 0x%x, vid 0x%x\n",
data->currfid, data->currvid);
- per_cpu(powernow_data, pol->cpu) = data;
+ /* Point all the CPUs in this policy to the same data */
+ for_each_cpu(cpu, pol->cpus)
+ per_cpu(powernow_data, cpu) = data;
return 0;
@@ -1155,6 +1157,7 @@ err_out:
static int powernowk8_cpu_exit(struct cpufreq_policy *pol)
struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
+ int cpu;
if (!data)
return -EINVAL;
@@ -1165,7 +1168,8 @@ static int powernowk8_cpu_exit(struct cpufreq_policy *pol)
- per_cpu(powernow_data, pol->cpu) = NULL;
+ for_each_cpu(cpu, pol->cpus)
+ per_cpu(powernow_data, cpu) = NULL;
return 0;