From: Thomas Renninger <trenn@suse.de>
Date: Tue, 2 Oct 2007 20:28:13 +0000 (-0700)
Subject: [CPUFREQ] Only check for transition latency on problematic governors (kconfig fix)
X-Git-Tag: v2.6.24-rc1~1396^2~5
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6afde10c3f58cc3ac593f5b4505b8b1cf719f5d6;p=linux-2.6

[CPUFREQ] Only check for transition latency on problematic governors (kconfig fix)

Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
---

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 418522f88f..65ac585112 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1484,17 +1484,30 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 					unsigned int event)
 {
 	int ret;
-	struct cpufreq_governor *gov = CPUFREQ_PERFORMANCE_GOVERNOR;
+
+	/* Only must be defined when default governor is known to have latency
+	   restrictions, like e.g. conservative or ondemand.
+	   That this is the case is already ensured in Kconfig
+	*/
+#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
+	struct cpufreq_governor *gov = &cpufreq_gov_performance;
+#else
+	struct cpufreq_governor *gov = NULL;
+#endif
 
 	if (policy->governor->max_transition_latency &&
 	    policy->cpuinfo.transition_latency >
 	    policy->governor->max_transition_latency) {
-		printk(KERN_WARNING "%s governor failed, too long"
-		       " transition latency of HW, fallback"
-		       " to %s governor\n",
-		       policy->governor->name,
-		       gov->name);
-		       policy->governor = gov;
+		if (!gov)
+			return -EINVAL;
+		else {
+			printk(KERN_WARNING "%s governor failed, too long"
+			       " transition latency of HW, fallback"
+			       " to %s governor\n",
+			       policy->governor->name,
+			       gov->name);
+			policy->governor = gov;
+		}
 	}
 
 	if (!try_module_get(policy->governor->owner))
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 9e5f5d0c87..450a841b58 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -286,8 +286,9 @@ static inline unsigned int cpufreq_quick_get(unsigned int cpu)
   Performance governor is fallback governor if any other gov failed to
   auto load due latency restrictions
 */
+#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
 extern struct cpufreq_governor cpufreq_gov_performance;
-#define CPUFREQ_PERFORMANCE_GOVERNOR	(&cpufreq_gov_performance)
+#endif
 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_performance)
 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)