[CPUFREQ] acpi-cpufreq: blacklist Intel 0f68: Fix HT detection and put in notification message

Removing the SMT/HT check, since the Errata doesn't mention
Hyper-Threading.

Adding in a printk, so that the user knows why acpi-cpufreq refuses to
load. Also, once system is blacklisted, don't repeat checks to see if
blacklisted. This also causes the message to only be printed once,
rather than for each CPU.

Signed-off-by: John L. Villalovos <[e-mail]>
Signed-off-by: Dave Jones <[e-mail]>

arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c

···
 
 static int acpi_cpufreq_blacklist(struct cpuinfo_x86 *c)
 {
-	/* http://www.intel.com/Assets/PDF/specupdate/314554.pdf
+	/* Intel Xeon Processor 7100 Series Specification Update
+	 * http://www.intel.com/Assets/PDF/specupdate/314554.pdf
 	 * AL30: A Machine Check Exception (MCE) Occurring during an
 	 * Enhanced Intel SpeedStep Technology Ratio Change May Cause
-	 * Both Processor Cores to Lock Up when HT is enabled*/
+	 * Both Processor Cores to Lock Up. */
 	if (c->x86_vendor == X86_VENDOR_INTEL) {
 		if ((c->x86 == 15) &&
 		    (c->x86_model == 6) &&
-		    (c->x86_mask == 8) && smt_capable())
+		    (c->x86_mask == 8)) {
+			printk(KERN_INFO "acpi-cpufreq: Intel(R) "
+			    "Xeon(R) 7100 Errata AL30, processors may "
+			    "lock up on frequency changes: disabling "
+			    "acpi-cpufreq.\n");
 			return -ENODEV;
+		    }
 		}
 	return 0;
 }
···
 	unsigned int result = 0;
 	struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
 	struct acpi_processor_performance *perf;
+#ifdef CONFIG_SMP
+	static int blacklisted;
+#endif
 
 	dprintk("acpi_cpufreq_cpu_init\n");
 
 #ifdef CONFIG_SMP
-	result = acpi_cpufreq_blacklist(c);
-	if (result)
-		return result;
+	if (blacklisted)
+		return blacklisted;
+	blacklisted = acpi_cpufreq_blacklist(c);
+	if (blacklisted)
+		return blacklisted;
 #endif
 
 	data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);