diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 0ee770d23d0e52998810113f662cb517549064c6..6a25d5d4283640f6a2ec76add7581a4bfd47e610 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -14,6 +14,12 @@
 #include <asm/swiotlb.h>
 #include <asm-generic/dma-coherent.h>
 
+#ifdef CONFIG_ISA
+# define ISA_DMA_BIT_MASK DMA_BIT_MASK(24)
+#else
+# define ISA_DMA_BIT_MASK DMA_BIT_MASK(32)
+#endif
+
 extern dma_addr_t bad_dma_address;
 extern int iommu_merge;
 extern struct device x86_dma_fallback_dev;
@@ -124,10 +130,8 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	if (dma_alloc_from_coherent(dev, size, dma_handle, &memory))
 		return memory;
 
-	if (!dev) {
+	if (!dev)
 		dev = &x86_dma_fallback_dev;
-		gfp |= GFP_DMA;
-	}
 
 	if (!is_device_dma_capable(dev))
 		return NULL;
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index b2a71dca5642c4fe513083783bd2b86e52532f41..a6e804d16c35a4053b5ba16323887007ef25c30d 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -45,12 +45,10 @@ int iommu_pass_through __read_mostly;
 dma_addr_t bad_dma_address __read_mostly = 0;
 EXPORT_SYMBOL(bad_dma_address);
 
-/* Dummy device used for NULL arguments (normally ISA). Better would
-   be probably a smaller DMA mask, but this is bug-to-bug compatible
-   to older i386. */
+/* Dummy device used for NULL arguments (normally ISA). */
 struct device x86_dma_fallback_dev = {
 	.init_name = "fallback device",
-	.coherent_dma_mask = DMA_BIT_MASK(32),
+	.coherent_dma_mask = ISA_DMA_BIT_MASK,
 	.dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
 };
 EXPORT_SYMBOL(x86_dma_fallback_dev);
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 745402e8e498a35f99c4f9819518936afc34bc7b..5b7056cec00c4ebcc74e0de01de421477dc27fad 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -656,8 +656,10 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
 	free_link_state(link);
 
 	/* Recheck latencies and configure upstream links */
-	pcie_update_aspm_capable(root);
-	pcie_config_aspm_path(parent_link);
+	if (parent_link) {
+		pcie_update_aspm_capable(root);
+		pcie_config_aspm_path(parent_link);
+	}
 out:
 	mutex_unlock(&aspm_lock);
 	up_read(&pci_bus_sem);