diff --git a/[refs] b/[refs]
index d56efc37ddfa..ca100557e632 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 55aab5f49e384a361668d112eefdb33e90779af9
+refs/heads/master: cf558d25e5c9f70fa0279c9b7b8b4aed7cae9bd4
diff --git a/trunk/arch/x86/kernel/amd_iommu_init.c b/trunk/arch/x86/kernel/amd_iommu_init.c
index c90a15eba5c5..c6cc22815d35 100644
--- a/trunk/arch/x86/kernel/amd_iommu_init.c
+++ b/trunk/arch/x86/kernel/amd_iommu_init.c
@@ -427,6 +427,10 @@ static u8 * __init alloc_command_buffer(struct amd_iommu *iommu)
 	memcpy_toio(iommu->mmio_base + MMIO_CMD_BUF_OFFSET,
 			&entry, sizeof(entry));
 
+	/* set head and tail to zero manually */
+	writel(0x00, iommu->mmio_base + MMIO_CMD_HEAD_OFFSET);
+	writel(0x00, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
+
 	iommu_feature_enable(iommu, CONTROL_CMDBUF_EN);
 
 	return cmd_buf;
diff --git a/trunk/arch/x86/kernel/cpu/mcheck/mce_64.c b/trunk/arch/x86/kernel/cpu/mcheck/mce_64.c
index 1c838032fd37..4b031a4ac856 100644
--- a/trunk/arch/x86/kernel/cpu/mcheck/mce_64.c
+++ b/trunk/arch/x86/kernel/cpu/mcheck/mce_64.c
@@ -510,9 +510,12 @@ static void __cpuinit mce_cpu_features(struct cpuinfo_x86 *c)
  */
 void __cpuinit mcheck_init(struct cpuinfo_x86 *c)
 {
+	static cpumask_t mce_cpus = CPU_MASK_NONE;
+
 	mce_cpu_quirks(c);
 
 	if (mce_dont_init ||
+	    cpu_test_and_set(smp_processor_id(), mce_cpus) ||
 	    !mce_available(c))
 		return;
 
diff --git a/trunk/arch/x86/kernel/pci-gart_64.c b/trunk/arch/x86/kernel/pci-gart_64.c
index a35eaa379ff6..ba7ad83e20a8 100644
--- a/trunk/arch/x86/kernel/pci-gart_64.c
+++ b/trunk/arch/x86/kernel/pci-gart_64.c
@@ -745,8 +745,10 @@ void __init gart_iommu_init(void)
 	unsigned long scratch;
 	long i;
 
-	if (cache_k8_northbridges() < 0 || num_k8_northbridges == 0)
+	if (cache_k8_northbridges() < 0 || num_k8_northbridges == 0) {
+		printk(KERN_INFO "PCI-GART: No AMD GART found.\n");
 		return;
+	}
 
 #ifndef CONFIG_AGP_AMD64
 	no_agp = 1;