lkml.org 
[lkml]   [2022]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 00/22] Fallback to native backlight
    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).

    \
     
     \ /
      Last update: 2022-10-24 22:18    [W:4.843 / U:1.256 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site