[PATCH 0/1][SRU][F][G][unstable][OEM-5.10] Stop using get_scalar_status command in Dell AIO uart backlight driver Edit

[Stefan Bader]

On 17.12.20 09:08, AceLan Kao wrote:
> From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1865402
> 
> [Impact]
> The get_scalar_status command was provided by ODM engineer and was newly
> introduced to determinate whether scalar is responsible for the backlight
> adjustment. That guy asked the scalar vendor to add this command and the
> command works as expected. But there is already a command in the Dell AIO
> scalar UART command spec. which can do the same thing since 2015, and the
> newly introduced get_scalar_status command is undocumented. To prevent
> from introducing regression in the future and to align with what Windows
> uses, replace this command with get_display_mode command.
> 
> [Fix]
> Replace get_scalar_status command with get_display_mode command.
> 
> [Test]
> Verified on new Dell AIO platforms.
> 
> [Regression Potential]
> Low, the command is already in the spec. since 2015.

That does not necessarily mean it works. I am probably rather hesitant here
because I got burned a very long time ago when trying to fix some ACPI backlight
issue. This started to become a nightmare ping-ponging between fixing new
hardware while breaking older on in turn. Or the other way round.
So, as simple as it looks, imo, this should be upstream with some settle time
before going into a stable kernel.

-Stefan
> 
> Chia-Lin Kao (AceLan) (1):
>   UBUNTU: SAUCE: platform/x86: dell-uart-backlight: add get_display_mode
>     command
> 
>  drivers/platform/x86/dell-uart-backlight.c | 91 +++++++++++-----------
>  drivers/platform/x86/dell-uart-backlight.h |  7 +-
>  2 files changed, 52 insertions(+), 46 deletions(-)
> 


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