Hi Edward Lin, Am 18.08.2014 um 08:09 schrieb Edward Lin: > ACPI video is not functional on Lenovo B470e. > The brightness control is also broken with vendor mode. > The brightness control only works with intel_backlight. By looking at your description (and your patch) I'm wondering how exactly this problem made itself apparent? I'm having a similar (the same?) issue with my Sony Vaio VPCS12C5E. The backlight interface registered by ACPI does not work and I have to boot with the command line option "acpi_backlight=vendor". Even then two interfaces get registered "nv_backlight" and "sony", only one of which (nv_backlight) works. Desktop environments (GNOME in particular) seem to be confused by this, so I always have to change the brightness by writing directly into the "actual_brightness" file. I've reported this back in 2012 [1], but was told that it is an ACPI issue and so it never was fixed. Couldn't a similar patch be applied to the sony-laptop module? I've added Mattia Dongili to the discussion, hopefully he doesn't mind to take a look at this again. I'm glad to test any patches, but am not familiar enough with all of the internal structs to mess around with them for myself without breaking support for other users of this module, especially since my model was shipped with in two different versions: One with the internal Intel GPU and another with a dedicated Nvidia GPU. I'm afraid a simple DMI match might not be good enough in this case? Best regards, Karol Babioch [1]: http://www.spinics.net/lists/platform-driver-x86/msg03406.html
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