NAK: [PATCH 0/3][SRU][B][C][D] Can't adjust brightness on DELL UHD dGPU AIO

[Seth Forshee]

On Wed, Jan 30, 2019 at 05:10:23PM +0800, AceLan Kao wrote:
> BugLink: https://bugs.launchpad.net/bugs/1813877
> 
> [Impact]
> The dell-uart-backlight driver has been loaded, but the backlight is
> controller by graphics driver instead of scalar IC. The old way to
> determinate weather the driver should be loaded is not working anymore,
> since the behavior of scalar command, show firmware version, is not the
> same as old platforms.
> 
> [Fix]
> Using more a reliable command, get_scalar_status, to check if scalar is
> in charge of the AIO backlight.
> 
> [Test]
> Verified on new Dell AIO platforms.
> 
> [Regression Potential]
> Expected. The get_scalar_status command is not supported by the first
> generation AIO platforms, so the driver may not be loaded on old AIO
> machines due to get_scalar_status command returns 0. To ease the pain,
> the "force" parameter has been introduced to make the driver can be loaded
> regardless of the return value of get_scalar_status command.

Isn't there a way to do this without regressing the first-generation AIO
platforms? We shouldn't be breaking backlight control on older machines
to fix it on newer machines. Expecting users to supply a module paramter
to get their previously working backlight control back isn't acceptable.

Seth