In fact, I force the ACPI_OS_NAME to "Windows 2001" just to activate the same functions as in Windows. And now, that works like a charm. Would you please try the workaround ? It's easy, you just have to add
acpi_os_name="Windows 2001"
at the end of the line concerning your kernel in the menu.lst from /boot/grub/menu.lst.
I have found the solution !!!
In fact, I force the ACPI_OS_NAME to "Windows 2001" just to activate the same functions as in Windows. And now, that works like a charm. Would you please try the workaround ? It's easy, you just have to add
acpi_os_ name="Windows 2001"
at the end of the line concerning your kernel in the menu.lst from /boot/grub/ menu.lst.