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-rw-r--r--arch/x86/kernel/acpi/sleep.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 130711f1454..41bb130c31d 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -60,16 +60,25 @@ int acpi_save_state_mem(void)
header->video_mode = saved_video_mode;
header->wakeup_jmp_seg = acpi_wakeup_address >> 4;
+
+ /*
+ * Set up the wakeup GDT. We set these up as Big Real Mode,
+ * that is, with limits set to 4 GB. At least the Lenovo
+ * Thinkpad X61 is known to need this for the video BIOS
+ * initialization quirk to work; this is likely to also
+ * be the case for other laptops or integrated video devices.
+ */
+
/* GDT[0]: GDT self-pointer */
header->wakeup_gdt[0] =
(u64)(sizeof(header->wakeup_gdt) - 1) +
((u64)(acpi_wakeup_address +
((char *)&header->wakeup_gdt - (char *)acpi_realmode))
<< 16);
- /* GDT[1]: real-mode-like code segment */
+ /* GDT[1]: big real mode-like code segment */
header->wakeup_gdt[1] =
GDT_ENTRY(0x809b, acpi_wakeup_address, 0xfffff);
- /* GDT[2]: real-mode-like data segment */
+ /* GDT[2]: big real mode-like data segment */
header->wakeup_gdt[2] =
GDT_ENTRY(0x8093, acpi_wakeup_address, 0xfffff);