diff -r -u linux-2.6.10rc3/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c linux-2.6.10rc3-maf/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c
--- linux-2.6.10rc3/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c	2004-12-05 20:02:40.000000000 +0100
+++ linux-2.6.10rc3-maf/drivers/scsi/aic7xxx/aic7xxx_osm_pci.c	2004-12-10 21:31:51.000000000 +0100
@@ -226,10 +226,10 @@
 	}
 	pci_set_master(pdev);
 
-	mask_39bit = 0x7FFFFFFFFFULL;
 	if (sizeof(dma_addr_t) > 4
 	 && ahc_linux_get_memsize() > 0x80000000
 	 && pci_set_dma_mask(pdev, mask_39bit) == 0) {
+		mask_39bit = (dma_addr_t)0x7FFFFFFFFFULL;
 		ahc->flags |= AHC_39BIT_ADDRESSING;
 		ahc->platform_data->hw_dma_mask = mask_39bit;
 	} else {