Index: linux-2.6.29.1/drivers/scsi/qla2xxx/qla_isr.c
===================================================================
--- linux-2.6.29.1.orig/drivers/scsi/qla2xxx/qla_isr.c
+++ linux-2.6.29.1/drivers/scsi/qla2xxx/qla_isr.c
@@ -1983,7 +1983,13 @@ qla2x00_request_irqs(struct qla_hw_data 
 	/* If possible, enable MSI-X. */
 	if (!IS_QLA2432(ha) && !IS_QLA2532(ha) &&
 	    !IS_QLA8432(ha) && !IS_QLA8001(ha))
+#ifdef CONFIG_PREEMPT_RT
+		/* Observed IO timeouts with MSI iterrupts on -rt kernel. */
+		/* This code change forces the driver to use APIC interrupts. */
+		goto skip_msi;
+#else
 		goto skip_msix;
+#endif /* CONFIG_PREEMPT_RT */
 
 	if (IS_QLA2432(ha) && (ha->pdev->revision < QLA_MSIX_CHIP_REV_24XX ||
 		!QLA_MSIX_FW_MODE_1(ha->fw_attributes))) {
Index: linux-2.6.29.1/drivers/scsi/qla2xxx/qla_version.h
===================================================================
--- linux-2.6.29.1.orig/drivers/scsi/qla2xxx/qla_version.h
+++ linux-2.6.29.1/drivers/scsi/qla2xxx/qla_version.h
@@ -7,7 +7,7 @@
 /*
  * Driver version
  */
-#define QLA2XXX_VERSION      "8.03.00-k4"
+#define QLA2XXX_VERSION      "8.03.00-k4-rt1"
 
 #define QLA_DRIVER_MAJOR_VER	8
 #define QLA_DRIVER_MINOR_VER	3