On Monday 24 October 2022 21:58:57 Akihiko Odaki wrote: > Regarding the second limitation, I don't even understand the difference > between vendor and native. My guess is that a vendor backlight device uses > vendor-specific ACPI interface, and a native one directly uses hardware > registers. If my guess is correct, the difference between vendor and native > does not imply that both of them are likely to exist at the same time. As > the conclusion, there is no more motivation to try to de-duplicate the > vendor/native combination than to try to de-duplicate combination of devices > with a single type. Hello! I just want to point one thing. On some Dell laptops there are 3 different ways (= 3 different APIs) how to control display backlight. There is ACPI driver (uses ACPI), GPU/DRM driver (i915.ko; uses directly HW) and platform vendor driver (dell-laptop.ko; uses vendor BIOS or firmware API). Just every driver has different pre-calculated scaling values. So sometimes user wants to choose different driver just because it allows to set backlight level with "better" granularity. Registering all 3 device drivers is bad as user does not want to see 3 display panels and forcing registration of specific one without runtime option is also bad (some of those drivers do not have to be suitable or has worse granularity as other).
