Detecting BIOS CD device by INT13 "Check Extensions" (AH=42) call does
not work for all BIOSes.
This patch fixes this to allow access to the boot CD.
See also thread "[PATCH] Create floppy emulation boot CD with
grub-mkimage". The "(cd0" patch from Bean is not included here but
should also be applied.
Christian
2008-02-10 Christian Franke <[EMAIL PROTECTED]>
* disk/i386/pc/biosdisk.c: Include <grub/machine/kernel.h>.
(GRUB_MOD_INIT): Make boot CD accessible even if BIOS does not report
INT13 Extensions for grub_boot_drive.
* include/grub/i386/pc/biosdisk.h (GRUB_BIOSDISK_MACHINE_CDROM_START):
Change from 0xe0 to 0x9f to cover more BIOS variants.
* include/grub/i386/pc/kernel.h (grub_boot_drive): Add EXPORT_VAR.
diff -rup --exclude CVS grub2.orig/disk/i386/pc/biosdisk.c grub2/disk/i386/pc/biosdisk.c
--- grub2.orig/disk/i386/pc/biosdisk.c 2008-02-03 20:29:51.500000000 +0100
+++ grub2/disk/i386/pc/biosdisk.c 2008-02-10 12:26:25.843750000 +0100
@@ -18,6 +18,7 @@
#include <grub/machine/biosdisk.h>
#include <grub/machine/memory.h>
+#include <grub/machine/kernel.h>
#include <grub/disk.h>
#include <grub/dl.h>
#include <grub/mm.h>
@@ -391,6 +392,16 @@ GRUB_MOD_INIT(biosdisk)
}
}
+ /* Some BIOSes do not report INT13 Extensions for the
+ boot CD. Ensure that the boot CD can be accessed. */
+ if (! found
+ && GRUB_BIOSDISK_MACHINE_CDROM_START <= grub_boot_drive
+ && grub_boot_drive < GRUB_BIOSDISK_MACHINE_CDROM_END)
+ {
+ cd_start = grub_boot_drive;
+ found = 1;
+ }
+
cd_count = found;
}
diff -rup --exclude CVS grub2.orig/include/grub/i386/pc/biosdisk.h grub2/include/grub/i386/pc/biosdisk.h
--- grub2.orig/include/grub/i386/pc/biosdisk.h 2008-02-03 20:29:52.187500000 +0100
+++ grub2/include/grub/i386/pc/biosdisk.h 2008-02-09 15:55:04.713289500 +0100
@@ -25,7 +25,7 @@
#define GRUB_BIOSDISK_FLAG_LBA 1
#define GRUB_BIOSDISK_FLAG_CDROM 2
-#define GRUB_BIOSDISK_MACHINE_CDROM_START 0xe0
+#define GRUB_BIOSDISK_MACHINE_CDROM_START 0x9f
#define GRUB_BIOSDISK_MACHINE_CDROM_END 0xf0
struct grub_biosdisk_data
diff -rup --exclude CVS grub2.orig/include/grub/i386/pc/kernel.h grub2/include/grub/i386/pc/kernel.h
--- grub2.orig/include/grub/i386/pc/kernel.h 2008-02-03 20:29:52.375000000 +0100
+++ grub2/include/grub/i386/pc/kernel.h 2008-02-10 00:16:43.812500000 +0100
@@ -71,7 +71,7 @@ extern grub_int32_t grub_memdisk_image_s
extern char grub_prefix[];
/* The boot BIOS drive number. */
-extern grub_int32_t grub_boot_drive;
+extern grub_int32_t EXPORT_VAR(grub_boot_drive);
/* The root BIOS drive number. */
extern grub_int32_t grub_root_drive;
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