Re: [PATCH 00/22] Fallback to native backlight

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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).



[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]

  Powered by Linux