Solution to switch on/off graphics card for the Lenovo IdeaPad U330

The Lenovo IdeaPad U330 is another hybrid graphics laptop produced by Lenovo. By switching off the ATI card on the U330 model, the power consumption reduces from 23W to 13W.

Check out this package:
http://ljr.free.fr/archives/lenovo_u330/

Or simply manually install:

Makefile:
=====
ifneq ($(KERNELRELEASE),)
    obj-m := lenovo_acpi.o
else
    KERNELDIR ?= /lib/modules/$(shell uname -r)/build
    PWD := $(shell pwd)


default:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) $(EXTRA_FLAGS) modules

clean:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) $(EXTRA_FLAGS) clean

endif
=========

lenovo_acpi.c
======
/* Linux kernel module that disables the discrete graphics board for Lenovo
 * U330. Other lenovo laptops could work, but I don't know.
 *
 * Copyright (c) 2009: Sylvain Joyeux <sylvain.joyeux@m4x.org>
 */
#include <acpi/acpi.h>

MODULE_LICENSE("GPL");

static acpi_handle root_handle;

static int __init kill_ati(void)
{
    int i;
    acpi_status status;
    // The device handle
    acpi_handle handle;
    // The package elements
    union acpi_object package_elements[3];
    // The arguments to ATPX
    union acpi_object atpx_arg_elements[2];
    struct acpi_object_list atpx_arg;
    // For the return value of ATPX
    struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

    status = acpi_get_handle(root_handle, "\\_SB_.PCI0.OVGA.ATPX", &handle);
    if (ACPI_FAILURE(status))
    {
        status = acpi_get_handle(root_handle, "\\_SB_.PCI0.OVGA.XTPX", &handle);
        if (ACPI_FAILURE(status))
        {
            printk("lenovo_acpi: cannot get ACPI handle: %s\n", acpi_format_exception(status));
            return -ENOSYS;
        }
        printk("lenovo_acpi: in discrete graphics mode\n");
        return 0;
    }

    for (i = 0; i < 3; ++i)
    {
        package_elements[i].type = ACPI_TYPE_INTEGER;
        package_elements[i].integer.value = 0;
    }

    atpx_arg.count = 2;
    atpx_arg.pointer = &atpx_arg_elements[0];

    atpx_arg_elements[0].type = ACPI_TYPE_INTEGER;
    atpx_arg_elements[0].integer.value = 2;

    atpx_arg_elements[1].type = ACPI_TYPE_PACKAGE;
    atpx_arg_elements[1].package.count = 3;
    atpx_arg_elements[1].package.elements = &package_elements[0];
   
    status = acpi_evaluate_object(handle, NULL, &atpx_arg, &buffer);
    if (ACPI_FAILURE(status))
    {
        printk("lenovo_acpi: ATPX method call failed: %s\n", acpi_format_exception(status));
        return -ENOSYS;
    }
    kfree(buffer.pointer);

    printk("lenovo_acpi: disabled the discrete graphics card\n");
    return 0;
}

static void dummy(void)
{
}

module_init(kill_ati);
module_exit(dummy);
===============