Hi, Maciej-san > What is the "gdt body must be addressable from real mode" requirement >about? GDT is addressed by the CPU using a linear address as obtained >from GDTR (bypassing segmentation, for obvious reasons) and is accessible >regardless of its placement within the 32-bit linear address space in all >CPU modes. As its a linear address it only undergoes translation at the >page level, if enabled. The same applies to IDT. I believe this patch is required because the original gdt is not addressable via the low mapping page table (set by acpi_save_state_mem and used for wakeup code), not the GDTR's linear address size reason. cc:Shaohua and Len wakeup_gdt2.patch should be slightestly modified to wakeup_gdt_2.6.10.patch because %edx is conflict with msr's patch in 2.6.10-rc2 or later. thanks -Hiro