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Thread: Lenovo Ideapad Y510 is Go (Continued / NEW)

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  1. #11
    Join Date
    Aug 2008
    JHB, South Africa
    Ubuntu 8.10 Intrepid Ibex

    Smile Re: Lenovo Ideapad Y510 is Go (Continued / NEW)

    Good News Everyone!

    I have a correctly working backlight on my Ideapad Y510! ...

    This has been achieved by using a custom DSDT, and nothing else, no fiddling with ACPI or HAL or anything like that.

    After days of trawling and scrolling through the original DSDT I finally figured out that the Lenovo emedded controller seems to be expecting some specific input values, and that there seemed to be a slight mistake in the "Package" of values returned by the _BCL AML method. Additionally ACPI as bundled with Ubuntu and the Kernel at the moment, expects the values to be in the correct order, i.e. <value when on AC>, <value when on Battery>, val0, val1, val2 ...etc the most important thing to note is that ACPI at the moment does not appear to sort the values, and assumes that they are from lowest to highest. In the case of the Ideapad they seem to have been reversed.

    I have attached the DSDT.dsl in BZIP2 format to this post for those who want to give this a go.

    You will obviously need the Intel ASL compiler:

    sudo apt-get install iasl
    To compile the DSDT just run:

    iasl DSDT.dsl
    Once it's compiled put it into the initramfs-tools directory under /etc:

    sudo cp DSDT.aml /etc/initramfs-tools/
    You might need to install the initramfs-tools package

    sudo apt-get install initramfs-tools
    and then finally regenerate the initrd image

    sudo mkinitramfs -o /boot/initrd.img-`uname -r`
    reboot the machine and then give it a go...

    Please test this and let me know if anyone is experiencing any other difficulties...

    Cheers all!
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