Index: uspace/drv/ehci-hcd/main.c
===================================================================
--- uspace/drv/ehci-hcd/main.c	(revision 5da18c76612acf93ca259e5e62047d10590b3416)
+++ uspace/drv/ehci-hcd/main.c	(revision 109d55cf4b5cb06ac7111270941a58a4f3a48b11)
@@ -88,5 +88,5 @@
 	ret = pci_disable_legacy(device, reg_base, reg_size, irq);
 	CHECK_RET_RETURN(ret,
-	    "Failed(%d) disable legacy USB: %s.\n", ret, str_error(ret));
+	    "Failed to disable legacy USB: %s.\n", str_error(ret));
 
 	ddf_fun_t *hc_fun = ddf_fun_create(device, fun_exposed, "ehci-hc");
Index: uspace/drv/ehci-hcd/pci.c
===================================================================
--- uspace/drv/ehci-hcd/pci.c	(revision 5da18c76612acf93ca259e5e62047d10590b3416)
+++ uspace/drv/ehci-hcd/pci.c	(revision 109d55cf4b5cb06ac7111270941a58a4f3a48b11)
@@ -35,4 +35,5 @@
  */
 #include <errno.h>
+#include <str_error.h>
 #include <assert.h>
 #include <as.h>
@@ -240,6 +241,6 @@
 	void *regs = NULL;
 	int ret = pio_enable((void*)reg_base, reg_size, &regs);
-	CHECK_RET_RETURN(ret, "Failed(%d) to map registers %p.\n",
-	    ret, (void *) reg_base);
+	CHECK_RET_RETURN(ret, "Failed to map registers %p: %s.\n",
+	    (void *) reg_base, str_error(ret));
 
 	const uint32_t hcc_params =
@@ -256,5 +257,5 @@
 	uint32_t usblegsup;
 	ret = pci_read32(device, eecp + USBLEGSUP_OFFSET, &usblegsup);
-	CHECK_RET_RETURN(ret, "Failed(%d) to read USBLEGSUP.\n", ret);
+	CHECK_RET_RETURN(ret, "Failed to read USBLEGSUP: %s.\n", str_error(ret));
 	usb_log_debug("USBLEGSUP: %" PRIxn ".\n", usblegsup);
 
@@ -263,5 +264,6 @@
 	usb_log_debug("Requesting OS control.\n");
 	ret = pci_write8(device, eecp + USBLEGSUP_OFFSET + 3, 1);
-	CHECK_RET_RETURN(ret, "Failed(%d) to request OS EHCI control.\n", ret);
+	CHECK_RET_RETURN(ret, "Failed to request OS EHCI control: %s.\n",
+	    str_error(ret));
 
 	size_t wait = 0;
@@ -283,5 +285,6 @@
 		ret = pci_write32(device, eecp + USBLEGSUP_OFFSET,
 		    USBLEGSUP_OS_CONTROL);
-		CHECK_RET_RETURN(ret, "Failed(%d) to force OS control.\n", ret);
+		CHECK_RET_RETURN(ret, "Failed to force OS control: %s.\n",
+		    str_error(ret));
 		/* Check capability type here, A value of 01h
 		 * identifies the capability as Legacy Support.
@@ -297,5 +300,5 @@
 			    device, eecp + USBLEGCTLSTS_OFFSET, &usblegctlsts);
 			CHECK_RET_RETURN(ret,
-			    "Failed(%d) to get USBLEGCTLSTS.\n", ret);
+			    "Failed to get USBLEGCTLSTS: %s.\n", str_error(ret));
 			usb_log_debug("USBLEGCTLSTS: %" PRIxn ".\n",
 			    usblegctlsts);
@@ -310,5 +313,6 @@
 			    device, eecp + USBLEGCTLSTS_OFFSET, &usblegctlsts);
 			CHECK_RET_RETURN(ret,
-			    "Failed(%d) to get USBLEGCTLSTS 2.\n", ret);
+			    "Failed to get USBLEGCTLSTS 2: %s.\n",
+			    str_error(ret));
 			usb_log_debug("Zeroed USBLEGCTLSTS: %" PRIxn ".\n",
 			    usblegctlsts);
@@ -319,5 +323,5 @@
 	/* Read again Legacy Support register */
 	ret = pci_read32(device, eecp + USBLEGSUP_OFFSET, &usblegsup);
-	CHECK_RET_RETURN(ret, "Failed(%d) to read USBLEGSUP.\n", ret);
+	CHECK_RET_RETURN(ret, "Failed to read USBLEGSUP: %s.\n", str_error(ret));
 	usb_log_debug("USBLEGSUP: %" PRIxn ".\n", usblegsup);
 
Index: uspace/drv/ohci/hw_struct/hcca.h
===================================================================
--- uspace/drv/ohci/hw_struct/hcca.h	(revision 5da18c76612acf93ca259e5e62047d10590b3416)
+++ uspace/drv/ohci/hw_struct/hcca.h	(revision 109d55cf4b5cb06ac7111270941a58a4f3a48b11)
@@ -37,4 +37,7 @@
 #include <stdint.h>
 
+/** Host controller communication area.
+ * Shared memory used for communication between the controller and the driver.
+ */
 typedef struct hcca {
 	uint32_t int_ep[32];