libdrm to read/write drm_dpcd helper functions.

[Jani Nikula]

On Fri, 25 May 2018, lester magtagad <lester.magtagad at gmail.com> wrote:
> Hello everyone,
>
> I am new to DRM and linux, I started reading developers guide and research
> on my own.
>
> I don't know where to start on how to communicate the DP helper functions
> (drm_dp_dpcd_read,  drm_dp_dpcd_readb,  drm_dp_dpcd_write,
> drm_dp_dpcd_writeb),
> what will I include(#include<sample.h>) in my main program. I already have
> drm in my setup(kernel version:4.4.21-69), I also have libdrm-2.4.92 API  ,
> the problem is I don't really have an idea on how use it.
>
> My main objective is I want to read and write brightness/backlight level on
> DP connections.
>
> Is it possible to use only the libdrm api to import DP helper functions?if
> yes how?
>
> Maybe someone can help/guide me on this?

Where does the sudden interest with DPCD access from userspace come
from? See the thread [1]. My replies there should cover this.

I'm starting to wonder if this is an XY problem...

BR,
Jani.


[1] http://mid.mail-archive.com/471791572.2287221.1526561265798@mail.yahoo.com


-- 
Jani Nikula, Intel Open Source Graphics Center