[PATCH] acpi: always scan the BIOS region if searching the EBDA fails

[David Michael]

---
This can be applied on top of the ACPI halt patches from Justus to test
powering off QEMU systems.

 i386/i386at/acpi.c | 31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/i386/i386at/acpi.c b/i386/i386at/acpi.c
index ec8aeb1..488aa6d 100644
--- a/i386/i386at/acpi.c
+++ b/i386/i386at/acpi.c
@@ -30,13 +30,12 @@ grub_machine_acpi_get_rsdpv1 (void)
   grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
   ebda = (grub_uint8_t *) phystokv ((* ((grub_uint16_t *) phystokv (0x40e))) 
<< 4);
   ebda_len = * (grub_uint16_t *) ebda;
-  if (! ebda_len)
-    return 0;
-  for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
-    if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
-       && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
-       && ((struct grub_acpi_rsdp_v10 *) ptr)->revision == 0)
-      return (struct grub_acpi_rsdp_v10 *) ptr;
+  if (ebda_len)
+    for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
+      if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
+         && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
+         && ((struct grub_acpi_rsdp_v10 *) ptr)->revision == 0)
+       return (struct grub_acpi_rsdp_v10 *) ptr;
 
   grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
   for (ptr = (grub_uint8_t *) phystokv (0xe0000); ptr < (grub_uint8_t *) 
phystokv (0x100000);
@@ -57,16 +56,14 @@ grub_machine_acpi_get_rsdpv2 (void)
   grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
   ebda = (grub_uint8_t *) phystokv ((* ((grub_uint16_t *) phystokv (0x40e))) 
<< 4);
   ebda_len = * (grub_uint16_t *) ebda;
-  if (! ebda_len)
-    return 0;
-  for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
-    if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
-       && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
-       && ((struct grub_acpi_rsdp_v10 *) ptr)->revision != 0
-       && ((struct grub_acpi_rsdp_v20 *) ptr)->length < 1024
-       && grub_byte_checksum (ptr, ((struct grub_acpi_rsdp_v20 *) ptr)->length)
-       == 0)
-      return (struct grub_acpi_rsdp_v20 *) ptr;
+  if (ebda_len)
+    for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
+      if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
+         && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
+         && ((struct grub_acpi_rsdp_v10 *) ptr)->revision != 0
+         && ((struct grub_acpi_rsdp_v20 *) ptr)->length < 1024
+         && grub_byte_checksum (ptr, ((struct grub_acpi_rsdp_v20 *) 
ptr)->length) == 0)
+       return (struct grub_acpi_rsdp_v20 *) ptr;
 
   grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
   for (ptr = (grub_uint8_t *) phystokv (0xe0000); ptr < (grub_uint8_t *) 
phystokv (0x100000);
-- 
1.9.3