--- linux-2.3.paul/drivers/video/controlfb.c	Fri Feb 11 00:20:08 2000
+++ linux-2.3.paul-work/drivers/video/controlfb.c	Sun Mar 19 12:36:30 2000
@@ -678,7 +678,7 @@
 {
 	struct fb_info_control	*p;
 	unsigned long		addr, size;
-	int			i, bank1, bank2;
+	int			i, bank1, bank2, m[7];
 
 	if(dp->n_addrs != 2) {
 		printk(KERN_ERR "expecting 2 address for control (got %d)", dp->n_addrs);
@@ -714,7 +714,70 @@
 	 * - with 2M vram in bank 2, it appears only at offset 6M
 	 * - with 4M vram, it appears only as a 4M block at offset 0.
 	 */
+#if (1)
+	/* Let's do the mem test... */
+	for (i=0; i<7; i++) m[i]=0;
 
+	out_8(&p->frame_buffer[0], 0x5a);
+	out_8(&p->frame_buffer[1], 0xc7);
+	asm volatile("eieio; dcbi 0,%0" : : "r" (&p->frame_buffer[0]) : "memory" );
+	m[0] =  (in_8(&p->frame_buffer[0x000000]) == 0x5a)
+		&& (in_8(&p->frame_buffer[0x000001]) == 0xc7);
+	m[2] =  (in_8(&p->frame_buffer[0x200000]) == 0x5a)
+		&& (in_8(&p->frame_buffer[0x200001]) == 0xc7);
+	m[4] =  (in_8(&p->frame_buffer[0x400000]) == 0x5a)
+		&& (in_8(&p->frame_buffer[0x400001]) == 0xc7);
+	m[6] =  (in_8(&p->frame_buffer[0x600000]) == 0x5a)
+		&& (in_8(&p->frame_buffer[0x600001]) == 0xc7);
+
+	printk(KERN_INFO "control: mem at 0x000000: %s", m[0] ? "yes" : "no");
+	printk(", mirrored at:%s%s%s\n", m[2]?" 2M":"", m[4]?" 4M":"", m[6]?" 6M":"");
+
+	out_8(&p->frame_buffer[0x200000], 0xa5);
+	out_8(&p->frame_buffer[0x200001], 0x38);
+	asm volatile("eieio; dcbi 0,%0" : : "r" (&p->frame_buffer[0x200000]) : "memory" );
+	m[0] =  (in_8(&p->frame_buffer[0x000000]) == 0xa5)
+		&& (in_8(&p->frame_buffer[0x000001]) == 0x38);
+	m[2] =  (in_8(&p->frame_buffer[0x200000]) == 0xa5)
+		&& (in_8(&p->frame_buffer[0x200001]) == 0x38);
+	m[4] =  (in_8(&p->frame_buffer[0x400000]) == 0xa5)
+		&& (in_8(&p->frame_buffer[0x400001]) == 0x38);
+	m[6] =  (in_8(&p->frame_buffer[0x600000]) == 0xa5)
+		&& (in_8(&p->frame_buffer[0x600001]) == 0x38);
+
+	printk(KERN_INFO "control: mem at 0x200000: %s", m[2] ? "yes" : "no");
+	printk(", mirrored at:%s%s%s\n", m[0]?" 0M":"", m[4]?" 4M":"", m[6]?" 6M":"");
+
+	out_8(&p->frame_buffer[0x400000], 0xc1);
+	out_8(&p->frame_buffer[0x400001], 0x02);
+	asm volatile("eieio; dcbi 0,%0" : : "r" (&p->frame_buffer[0x400000]) : "memory" );
+	m[0] =  (in_8(&p->frame_buffer[0x000000]) == 0xc1)
+		&& (in_8(&p->frame_buffer[0x000001]) == 0x02);
+	m[2] =  (in_8(&p->frame_buffer[0x200000]) == 0xc1)
+		&& (in_8(&p->frame_buffer[0x200001]) == 0x02);
+	m[4] =  (in_8(&p->frame_buffer[0x400000]) == 0xc1)
+		&& (in_8(&p->frame_buffer[0x400001]) == 0x02);
+	m[6] =  (in_8(&p->frame_buffer[0x600000]) == 0xc1)
+		&& (in_8(&p->frame_buffer[0x600001]) == 0x02);
+
+	printk(KERN_INFO "control: mem at 0x400000: %s", m[4] ? "yes" : "no");
+	printk(", mirrored at:%s%s%s\n", m[0]?" 0M":"", m[2]?" 2M":"", m[6]?" 6M":"");
+
+	out_8(&p->frame_buffer[0x600000], 0xb3);
+	out_8(&p->frame_buffer[0x600001], 0x71);
+	asm volatile("eieio; dcbi 0,%0" : : "r" (&p->frame_buffer[0x600000]) : "memory" );
+	m[0] =  (in_8(&p->frame_buffer[0x000000]) == 0xb3)
+		&& (in_8(&p->frame_buffer[0x000001]) == 0x71);
+	m[2] =  (in_8(&p->frame_buffer[0x200000]) == 0xb3)
+		&& (in_8(&p->frame_buffer[0x200001]) == 0x71);
+	m[4] =  (in_8(&p->frame_buffer[0x400000]) == 0xb3)
+		&& (in_8(&p->frame_buffer[0x400001]) == 0x71);
+	m[6] =  (in_8(&p->frame_buffer[0x600000]) == 0xb3)
+		&& (in_8(&p->frame_buffer[0x600001]) == 0x71);
+
+	printk(KERN_INFO "control: mem at 0x600000: %s", m[6] ? "yes" : "no");
+	printk(", mirrored at:%s%s%s\n", m[0]?" 0M":"", m[2]?" 2M":"", m[4]?" 4M":"");
+#endif
 	/* We know there is something at 2M if there is something at 0M. */
 	out_8(&p->frame_buffer[0x200000], 0xa5);
 	out_8(&p->frame_buffer[0x200001], 0x38);