diff --git a/sys/dev/pms/freebsd/driver/ini/src/agdef.h b/sys/dev/pms/freebsd/driver/ini/src/agdef.h
--- a/sys/dev/pms/freebsd/driver/ini/src/agdef.h
+++ b/sys/dev/pms/freebsd/driver/ini/src/agdef.h
@@ -62,7 +62,7 @@
 #define AGTIAPI_MAX_DEVICE_7H       256 /*Max devices per channel in 7H */
 #define AGTIAPI_MAX_DEVICE_8H       512 /*Max devices per channel in 8H*/
 #define AGTIAPI_MAX_CAM_Q_DEPTH     1024
-#define AGTIAPI_NSEGS               (maxphys / PAGE_SIZE)
+#define AGTIAPI_NSEGS               (btoc(maxphys) + 1)
 /*
 ** Adapter specific defines 
 */
diff --git a/sys/dev/pms/freebsd/driver/ini/src/agtiapi.c b/sys/dev/pms/freebsd/driver/ini/src/agtiapi.c
--- a/sys/dev/pms/freebsd/driver/ini/src/agtiapi.c
+++ b/sys/dev/pms/freebsd/driver/ini/src/agtiapi.c
@@ -1833,7 +1833,8 @@
     cpi->hba_eng_cnt = 0;
     cpi->max_target = maxTargets - 1;
     cpi->max_lun = AGTIAPI_MAX_LUN;
-    cpi->maxio = 1024 *1024; /* Max supported I/O size, in bytes. */
+    /* Max supported I/O size, in bytes. */
+    cpi->maxio = ulmin(1024 * 1024, maxphys);
     cpi->initiator_id = 255;
     strlcpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
     strlcpy(cpi->hba_vid, "PMC", HBA_IDLEN);