Do install-time configuration of the i386 boot0 boot manager. At

present, this is limited to turning on the packet option if any of
disk slices begin above cylinder 1023.  The effect of this change
should therefore be to automatically enable LBA support, as needed,
when installing FreeBSD.

Something-of-the-kind-requested-by: peter

1 files changed, 23 insertions, 1 deletions

diff --git a/lib/libdisk/write_disk.c b/lib/libdisk/write_disk.c
index 54025b2..0d261ea 100644
--- a/lib/libdisk/write_disk.c
+++ b/lib/libdisk/write_disk.c
@@ -163,6 +163,22 @@ Write_Int32(u_int32_t *p, u_int32_t v)
     bp[2] = (v >> 16) & 0xff;
     bp[3] = (v >> 24) & 0xff;
 }
+
+#ifndef __alpha__
+/*
+ * Special install-time configuration for the i386 boot0 boot manager.
+ */
+static void
+Cfg_Boot_Mgr(u_char *mbr, int edd)
+{
+    if (mbr[0x1b0] == 0x66 && mbr[0x1b1] == 0xbb) {
+	if (edd)
+	    mbr[0x1bb] |= 0x80;	/* Packet mode on */
+	else
+	    mbr[0x1bb] &= 0x7f;	/* Packet mode off */
+    }
+}
+#endif
 #endif
 
 int
@@ -180,6 +196,9 @@ Write_Disk(struct disk *d1)
 	int PC98_EntireDisk = 0;
 #else
 	int s[4];
+#ifndef __alpha__
+	int need_edd = 0;	/* Need EDD (packet interface) */
+#endif
 #endif
 	int one = 1;
 	int zero = 0;
@@ -255,6 +274,7 @@ Write_Disk(struct disk *d1)
 			dp[j].dp_ssect = 0xff;
 			dp[j].dp_shd = 0xff;
 			dp[j].dp_scyl = 0xff;
+			need_edd++;
 		} else {
 			dp[j].dp_ssect = i % d1->bios_sect;
 			i -= dp[j].dp_ssect++;
@@ -357,8 +377,10 @@ Write_Disk(struct disk *d1)
 			write_block(fd,WHERE(2+i,d1),&d1->bootmenu[i * 512]);
 #else
 	mbr = read_block(fd,WHERE(0,d1));
-	if (d1->bootmgr)
+	if (d1->bootmgr) {
 		memcpy(mbr,d1->bootmgr,DOSPARTOFF);
+		Cfg_Boot_Mgr(mbr, need_edd);
+        }
 	memcpy(mbr+DOSPARTOFF,dp,sizeof *dp * NDOSPART);
 	mbr[512-2] = 0x55;
 	mbr[512-1] = 0xaa;