On Sat, 18 Apr 2015, Marc Ludwig Brotbuechsenleasing@gmx.de wrote:

Hi, Folks!

I'am looking for an opportunity to access the I2C-Interface which is attached to my displayport link. Can anyone give me a hint aubout an minimal working example for this?

I tried to figure aut how this could be solved using the linux userspace, but for me it looks like i have to implement my own driver according to https://www.kernel.org/doc/htmldocs/drm/ch02s05.html#idp10812112 this should be done by describing an drm_dp_aux_msg structure, which is passed into a driver's .transfer implementation.

You may be conflating two things here. DP has a native AUX channel, and I2C-over-AUX on top. If it's DDC you're after, you want I2C, and the I2C adapters are exposed to userspace. You might want to have a look at ddccontrol [1]. It's not minimal and seems to be abandoned, but last time I tried I could use it to control my monitor.

If it's DP AUX you're after (why?) there was some discussion about adding such an interface in the thread starting at [2].

BR, Jani.

[1] http://ddccontrol.sourceforge.net/ [2] http://mid.gmane.org/1428493301-20293-1-git-send-email-durgadoss.r@intel.com

Furthermore i was looking into some packages (the working machine runs an ArchLinux-Distro) which where provided. $ extra/libdrm 2.4.60-2 :Userspace interface to kernel DRM services $ extra/libva-intel-driver 1.5.1-1 : VA-API implementation for Intel G45 and HD Graphics family (the working machine has an Intel HD4000 GPU) But none of them does provide such helper functions.

Thank you for your time, with kind Regards,

Marc _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel