On Thu, 24 May 2018, John Sledge john_sledget@yahoo.com wrote:
I was able to update my kernel to 4.6 which has the DRM_DP_AUX_CHARDEV in the Kconfig file linux-4.6\drivers\gpu\drm. Though I also add DRM_DP_AUX_CHARDEV=y in kernel config. When invoke uname -r, I could see that the kernel is now 4.6.
If you're updating kernels, why not update to a recent kernel that's actually supported...?
How can I verify the DRM_DP_AUX_CHARDEV takes effect or got configure it correctly?
Boot the kernel, run 'ls /dev/drm_dp_aux*'. If you see stuff, you got it right.
It still unclear to me how to follow what you mean by using DRM DP AUX interface and getting /dev/drm_dp_auxN node(s) that allows me to read and write arbitrary DPCD offsets.
The device is a char device you can open, seek to an offset (which would be the DPCD offset), and read. For testing, you can achieve the same using dd.
BR, Jani.