X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=arch%2Fx86%2Fkernel%2Fcpu%2Fcpufreq%2Facpi-cpufreq.c;h=19f6b9d27e83288fb516e59a490c6e08f55a9a64;hb=32fb6c17566ec66de87324a834c7776f40e35e78;hp=05209b5cc6ca47959c063fbd1b8c480ab7b0f7cd;hpb=45e36c1666aa6c8b0c538abcf984b336184d8c3f;p=linux-2.6-omap-h63xx.git

diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index 05209b5cc6c..19f6b9d27e8 100644
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -682,6 +682,18 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 			    perf->states[i].transition_latency * 1000;
 	}
 
+	/* Check for high latency (>20uS) from buggy BIOSes, like on T42 */
+	if (perf->control_register.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
+	    policy->cpuinfo.transition_latency > 20 * 1000) {
+		static int print_once;
+		policy->cpuinfo.transition_latency = 20 * 1000;
+		if (!print_once) {
+			print_once = 1;
+			printk(KERN_INFO "Capping off P-state tranision latency"
+				" at 20 uS\n");
+		}
+	}
+
 	data->max_freq = perf->states[0].core_frequency * 1000;
 	/* table init */
 	for (i = 0; i < perf->state_count; i++) {