diff --git a/drivers/infiniband/hw/qib/qib.h b/drivers/infiniband/hw/qib/qib.h
index ffd48bfc4923457e5383345acfa3620fa5f6a52f..ba5173e249738cb123560a29701bdacb496e9fc8 100644
--- a/drivers/infiniband/hw/qib/qib.h
+++ b/drivers/infiniband/hw/qib/qib.h
@@ -1136,7 +1136,6 @@ extern struct qib_devdata *qib_lookup(int unit);
 extern u32 qib_cpulist_count;
 extern unsigned long *qib_cpulist;
 
-extern unsigned qib_wc_pat;
 extern unsigned qib_cc_table_size;
 int qib_init(struct qib_devdata *, int);
 int init_chip_wc_pat(struct qib_devdata *dd, u32);
diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
index 9ea6c440a00ca7012f6422f1ffd7f525b8d80548..725881890c4a217247993f9fbb933ff11bb27e27 100644
--- a/drivers/infiniband/hw/qib/qib_file_ops.c
+++ b/drivers/infiniband/hw/qib/qib_file_ops.c
@@ -835,7 +835,8 @@ static int mmap_piobufs(struct vm_area_struct *vma,
 	vma->vm_flags &= ~VM_MAYREAD;
 	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND;
 
-	if (qib_wc_pat)
+	/* We used PAT if wc_cookie == 0 */
+	if (!dd->wc_cookie)
 		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
 
 	ret = io_remap_pfn_range(vma, vma->vm_start, phys >> PAGE_SHIFT,
diff --git a/drivers/infiniband/hw/qib/qib_iba6120.c b/drivers/infiniband/hw/qib/qib_iba6120.c
index 0d2ba59af30af66bce01ef8132c8182cc6e44a33..4b927809d1a1191004799435c7aa9163d8d6f086 100644
--- a/drivers/infiniband/hw/qib/qib_iba6120.c
+++ b/drivers/infiniband/hw/qib/qib_iba6120.c
@@ -3315,11 +3315,9 @@ static int init_6120_variables(struct qib_devdata *dd)
 	qib_6120_config_ctxts(dd);
 	qib_set_ctxtcnt(dd);
 
-	if (qib_wc_pat) {
-		ret = init_chip_wc_pat(dd, 0);
-		if (ret)
-			goto bail;
-	}
+	ret = init_chip_wc_pat(dd, 0);
+	if (ret)
+		goto bail;
 	set_6120_baseaddrs(dd); /* set chip access pointers now */
 
 	ret = 0;
diff --git a/drivers/infiniband/hw/qib/qib_iba7220.c b/drivers/infiniband/hw/qib/qib_iba7220.c
index 22affda8af88eacbd11f21abab55ba299dfb0e0b..00b2af211157b5513092e495d62a0a014a1e1c2f 100644
--- a/drivers/infiniband/hw/qib/qib_iba7220.c
+++ b/drivers/infiniband/hw/qib/qib_iba7220.c
@@ -4126,11 +4126,9 @@ static int qib_init_7220_variables(struct qib_devdata *dd)
 	qib_7220_config_ctxts(dd);
 	qib_set_ctxtcnt(dd);  /* needed for PAT setup */
 
-	if (qib_wc_pat) {
-		ret = init_chip_wc_pat(dd, 0);
-		if (ret)
-			goto bail;
-	}
+	ret = init_chip_wc_pat(dd, 0);
+	if (ret)
+		goto bail;
 	set_7220_baseaddrs(dd); /* set chip access pointers now */
 
 	ret = 0;
diff --git a/drivers/infiniband/hw/qib/qib_iba7322.c b/drivers/infiniband/hw/qib/qib_iba7322.c
index ef97b71c8f7dd713a77401f593c6a10320a046e6..f32b4628e9913e17dfd0606e1713945ff65930f2 100644
--- a/drivers/infiniband/hw/qib/qib_iba7322.c
+++ b/drivers/infiniband/hw/qib/qib_iba7322.c
@@ -6429,6 +6429,7 @@ static int qib_init_7322_variables(struct qib_devdata *dd)
 	unsigned features, pidx, sbufcnt;
 	int ret, mtu;
 	u32 sbufs, updthresh;
+	resource_size_t vl15off;
 
 	/* pport structs are contiguous, allocated after devdata */
 	ppd = (struct qib_pportdata *)(dd + 1);
@@ -6677,29 +6678,27 @@ static int qib_init_7322_variables(struct qib_devdata *dd)
 	qib_7322_config_ctxts(dd);
 	qib_set_ctxtcnt(dd);
 
-	if (qib_wc_pat) {
-		resource_size_t vl15off;
-		/*
-		 * We do not set WC on the VL15 buffers to avoid
-		 * a rare problem with unaligned writes from
-		 * interrupt-flushed store buffers, so we need
-		 * to map those separately here.  We can't solve
-		 * this for the rarely used mtrr case.
-		 */
-		ret = init_chip_wc_pat(dd, 0);
-		if (ret)
-			goto bail;
+	/*
+	 * We do not set WC on the VL15 buffers to avoid
+	 * a rare problem with unaligned writes from
+	 * interrupt-flushed store buffers, so we need
+	 * to map those separately here.  We can't solve
+	 * this for the rarely used mtrr case.
+	 */
+	ret = init_chip_wc_pat(dd, 0);
+	if (ret)
+		goto bail;
 
-		/* vl15 buffers start just after the 4k buffers */
-		vl15off = dd->physaddr + (dd->piobufbase >> 32) +
-			dd->piobcnt4k * dd->align4k;
-		dd->piovl15base	= ioremap_nocache(vl15off,
-						  NUM_VL15_BUFS * dd->align4k);
-		if (!dd->piovl15base) {
-			ret = -ENOMEM;
-			goto bail;
-		}
+	/* vl15 buffers start just after the 4k buffers */
+	vl15off = dd->physaddr + (dd->piobufbase >> 32) +
+		  dd->piobcnt4k * dd->align4k;
+	dd->piovl15base	= ioremap_nocache(vl15off,
+					  NUM_VL15_BUFS * dd->align4k);
+	if (!dd->piovl15base) {
+		ret = -ENOMEM;
+		goto bail;
 	}
+
 	qib_7322_set_baseaddrs(dd); /* set chip access pointers now */
 
 	ret = 0;
diff --git a/drivers/infiniband/hw/qib/qib_init.c b/drivers/infiniband/hw/qib/qib_init.c
index 2ee36953e234c46ff704bc6e5dfbed8339c09974..7e00470adc30223c183f0e287f7a7d0d9beff944 100644
--- a/drivers/infiniband/hw/qib/qib_init.c
+++ b/drivers/infiniband/hw/qib/qib_init.c
@@ -91,15 +91,6 @@ MODULE_PARM_DESC(krcvqs, "number of kernel receive queues per IB port");
 unsigned qib_cc_table_size;
 module_param_named(cc_table_size, qib_cc_table_size, uint, S_IRUGO);
 MODULE_PARM_DESC(cc_table_size, "Congestion control table entries 0 (CCA disabled - default), min = 128, max = 1984");
-/*
- * qib_wc_pat parameter:
- *      0 is WC via MTRR
- *      1 is WC via PAT
- *      If PAT initialization fails, code reverts back to MTRR
- */
-unsigned qib_wc_pat = 1; /* default (1) is to use PAT, not MTRR */
-module_param_named(wc_pat, qib_wc_pat, uint, S_IRUGO);
-MODULE_PARM_DESC(wc_pat, "enable write-combining via PAT mechanism");
 
 static void verify_interrupt(unsigned long);
 
@@ -1377,8 +1368,7 @@ static void cleanup_device_data(struct qib_devdata *dd)
 		spin_unlock(&dd->pport[pidx].cc_shadow_lock);
 	}
 
-	if (!qib_wc_pat)
-		qib_disable_wc(dd);
+	qib_disable_wc(dd);
 
 	if (dd->pioavailregs_dma) {
 		dma_free_coherent(&dd->pcidev->dev, PAGE_SIZE,
@@ -1547,14 +1537,12 @@ static int qib_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto bail;
 	}
 
-	if (!qib_wc_pat) {
-		ret = qib_enable_wc(dd);
-		if (ret) {
-			qib_dev_err(dd,
-				"Write combining not enabled (err %d): performance may be poor\n",
-				-ret);
-			ret = 0;
-		}
+	ret = qib_enable_wc(dd);
+	if (ret) {
+		qib_dev_err(dd,
+			"Write combining not enabled (err %d): performance may be poor\n",
+			-ret);
+		ret = 0;
 	}
 
 	qib_verify_pioperf(dd);
diff --git a/drivers/infiniband/hw/qib/qib_wc_x86_64.c b/drivers/infiniband/hw/qib/qib_wc_x86_64.c
index fe0850ac6883c498c8a09ef191876941323d581d..6d61ef98721cb02f6b4baeead132cbe1d399753c 100644
--- a/drivers/infiniband/hw/qib/qib_wc_x86_64.c
+++ b/drivers/infiniband/hw/qib/qib_wc_x86_64.c
@@ -116,21 +116,9 @@ int qib_enable_wc(struct qib_devdata *dd)
 	}
 
 	if (!ret) {
-		int cookie;
-
-		cookie = mtrr_add(pioaddr, piolen, MTRR_TYPE_WRCOMB, 1);
-		if (cookie < 0) {
-			{
-				qib_devinfo(dd->pcidev,
-					 "mtrr_add()  WC for PIO bufs failed (%d)\n",
-					 cookie);
-				ret = -EINVAL;
-			}
-		} else {
-			dd->wc_cookie = cookie;
-			dd->wc_base = (unsigned long) pioaddr;
-			dd->wc_len = (unsigned long) piolen;
-		}
+		dd->wc_cookie = arch_phys_wc_add(pioaddr, piolen);
+		if (dd->wc_cookie < 0)
+			ret = -EINVAL;
 	}
 
 	return ret;
@@ -142,18 +130,7 @@ int qib_enable_wc(struct qib_devdata *dd)
  */
 void qib_disable_wc(struct qib_devdata *dd)
 {
-	if (dd->wc_cookie) {
-		int r;
-
-		r = mtrr_del(dd->wc_cookie, dd->wc_base,
-			     dd->wc_len);
-		if (r < 0)
-			qib_devinfo(dd->pcidev,
-				 "mtrr_del(%lx, %lx, %lx) failed: %d\n",
-				 dd->wc_cookie, dd->wc_base,
-				 dd->wc_len, r);
-		dd->wc_cookie = 0; /* even on failure */
-	}
+	arch_phys_wc_del(dd->wc_cookie);
 }
 
 /**