On Tue, 2009-09-15 at 15:54 +0800, Rafał Miłecki wrote: > OK, you provided me fair amount of texts to read :) > > W dniu 15 września 2009 09:43 użytkownik Zhang Rui > <rui.zhang@xxxxxxxxx> napisał: > > And I think it may work for you as well, i.e. two backlight sysfs I/F > > may co-exist, it's the user space to decide which I/F to use. > > Could you explain, please, how does work Fn+F5 and Fn+F6 in > notebooks? I thought it generates some ACPI that kernel identifies as > backlight up/down and kernel passes it to module registered with: > backlight_device_register(...) > is that right? > No... the hotkey events can be controlled either by ACPI video device or by ACPI platform specific device, say sony-laptop. There are also other ways that ACPI is not involved but they're beyond my scope. :) If it's controlled via ACPI video device, the ACPI video backlight control usually works at this time. When hotkey is pressed, an ACPI notification is sent to ACPI video device, and then the backlight is changed via ACPI control methods (_BCM/_BCL/_BQC). If it's controlled in ACPI platform specific way, then the platform specific driver (e.g. sony-laptop) can catch the event when hotkey is pressed and invokes the platform specific methods to change the backlight. > Then two backlight devices would be a problem, I guess? > I agree. but we don't have any better idea for now. :( thanks, rui -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
