Re: [PATCH] Ensure boot CD can be accessed

[Christian Franke]

Bean wrote:
> On Feb 10, 2008 8:47 PM, Christian Franke <...> wrote:
>   
> > Bean wrote:
> >     
> > > On Feb 10, 2008 8:23 PM, Christian Franke <...> wrote:
> > >
> > >       
> > > > ...
> > > >         
> > > i think we can assume grub_boot_drive as (cd0) if it's within range,
> > > and start scanning from grub_boot_drive + 1.
> > >
> > >
> > >       
> > Yes, I will provide a new patch. Should it include your init.c patch?
> >     
>
> you can include it so that the changes can be committed at the same time.
>
>   

New patch below.

Christian

2008-02-10  Christian Franke  <address@hidden>

        * 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. Start CD scanning from
        grub_boot_drive + 1.
        * 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.
        * kern/i386/pc/init.c (make_install_device): Always set boot CD device
        name to "(cd0)". Patch was provided by Bean.



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 15:16:19.343750000 +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>
@@ -364,7 +365,8 @@ grub_disk_biosdisk_fini (void)
 
 GRUB_MOD_INIT(biosdisk)
 {
-  int drive, found = 0;
+  int drive = GRUB_BIOSDISK_MACHINE_CDROM_START;
+  int found = 0;
 
   if (grub_disk_firmware_is_tainted)
     {
@@ -375,8 +377,17 @@ GRUB_MOD_INIT(biosdisk)
 
   grub_disk_dev_register (&grub_biosdisk_dev);
 
-  for (drive = GRUB_BIOSDISK_MACHINE_CDROM_START;
-       drive < GRUB_BIOSDISK_MACHINE_CDROM_END; drive++)
+  /* Some BIOSes do not report INT13 Extensions for the
+     boot CD.  Ensure that the boot CD can be accessed.  */
+  if (GRUB_BIOSDISK_MACHINE_CDROM_START <= grub_boot_drive
+      && grub_boot_drive < GRUB_BIOSDISK_MACHINE_CDROM_END)
+    {
+      cd_start = grub_boot_drive;
+      drive = grub_boot_drive + 1;
+      found = 1;
+    }
+
+  for ( ; drive < GRUB_BIOSDISK_MACHINE_CDROM_END; drive++)
     {
       if (grub_biosdisk_check_int13_extensions (drive))
         {
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;
diff -rup --exclude CVS grub2.orig/kern/i386/pc/init.c grub2/kern/i386/pc/init.c
--- grub2.orig/kern/i386/pc/init.c      2008-02-03 20:29:53.125000000 +0100
+++ grub2/kern/i386/pc/init.c   2008-02-10 15:05:40.140625000 +0100
@@ -77,9 +77,9 @@ make_install_device (void)
       if (grub_root_drive == 0xFF)
         grub_root_drive = grub_boot_drive;
       
-      if (grub_root_drive >= GRUB_BIOSDISK_MACHINE_CDROM_START)
-        grub_sprintf (dev, "(cd%u",
-                     grub_root_drive - GRUB_BIOSDISK_MACHINE_CDROM_START);
+      if ((grub_root_drive >= GRUB_BIOSDISK_MACHINE_CDROM_START) &&
+          (grub_root_drive < GRUB_BIOSDISK_MACHINE_CDROM_END))
+       grub_strcpy (dev, "(cd0");
       else
         grub_sprintf (dev, "(%cd%u",
                      (grub_root_drive & 0x80) ? 'h' : 'f',