mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-18 00:24:58 +08:00
ca0d9eab0f
fujitsu-laptop registers two ACPI drivers: one for ACPI device FUJ02B1 enabling backlight control and another for ACPI device FUJ02E3 which handles various other stuff (hotkeys, LEDs, etc.) In a perfect world, private data used by each of these drivers would be neatly encapsulated in a structure specific to a given driver instance. Sadly, firmware present on some Fujitsu laptops makes that impossible by exposing backlight power control (which is what the FUJ02B1 ACPI device should take care of) through the FUJ02E3 ACPI device. This means the backlight driver needs a way to access an ACPI device it is not bound to. When the backlight driver is extracted into a separate module, it will not be able to rely on a module-wide variable any more and such access will happen through an API exposed by fujitsu-laptop. For all known firmwares out in the wild, it seems that whenever the FUJ02B1 ACPI device is present, it is always accompanied by a single instance of the FUJ02E3 ACPI device. We could independently grab an ACPI handle to the FUJ02E3 ACPI device from the backlight driver, but that would require using a hardcoded absolute path to that ACPI device, which is subject to change. It is easier to simply store a module-wide pointer to the last (most likely only) FUJ02E3 ACPI device found, make the aforementioned API use it and cover our bases by warning the user if firmware exposes multiple FUJ02E3 ACPI devices. Introducing this pointer in advance allows us to get rid of the acpi_handle field of struct fujitsu_bl and also enables a bit more step-by-step migration to a device-specific implementation of call_fext_func(). Signed-off-by: Michał Kępień <kernel@kempniu.pl> Reviewed-by: Jonathan Woithe <jwoithe@just42.net> Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org> |
||
|---|---|---|
| .. | ||
| chrome | ||
| goldfish | ||
| mips | ||
| olpc | ||
| x86 | ||
| Kconfig | ||
| Makefile | ||