diff -urN 2.4.6pre5/arch/i386/kernel/i386_ksyms.c 3c59x/arch/i386/kernel/i386_ksyms.c
--- 2.4.6pre5/arch/i386/kernel/i386_ksyms.c	Sat May 26 04:03:35 2001
+++ 3c59x/arch/i386/kernel/i386_ksyms.c	Sun Jun 24 22:11:14 2001
@@ -164,3 +164,9 @@
 #ifdef CONFIG_X86_PAE
 EXPORT_SYMBOL(empty_zero_page);
 #endif
+
+#ifdef CONFIG_HIGHMEM
+#include <linux/highmem.h>
+EXPORT_SYMBOL(highstart_pfn);
+EXPORT_SYMBOL(highend_pfn);
+#endif
diff -urN 2.4.6pre5/drivers/net/3c59x.c 3c59x/drivers/net/3c59x.c
--- 2.4.6pre5/drivers/net/3c59x.c	Thu Jun 21 08:03:41 2001
+++ 3c59x/drivers/net/3c59x.c	Sun Jun 24 22:10:17 2001
@@ -1257,7 +1257,14 @@
 #ifndef CONFIG_HIGHMEM
 		/* Actually, it still should work with iommu. */
 		dev->features |= NETIF_F_SG;
+#elif defined(__i386__) 
+		dev->features |= highstart_pfn==highend_pfn ?  NETIF_F_SG : 0; 
+#elif defined(__ppc__)
+#warn add your highmem test.	
 #endif
+		if (!(dev->features & NETIF_F_SG)) 
+			printk(KERN_WARNING "warning: zero copy support has been disabled.\n"); 
+
 		if (((hw_checksums[card_idx] == -1) && (vp->drv_flags & HAS_HWCKSM)) ||
 					(hw_checksums[card_idx] == 1)) {
 				dev->features |= NETIF_F_IP_CSUM;