Please attach your full dmesg output from when the driver loaded and your xorg log.

The driver is built in, I noticed Dave spotted the same (or similar issue) 

Harry Wentland said he sent a patch fixing the issue but I don't think it's included in your tree yet and I'm not sure which is the right patch

Thought I'd revert and retest with all the latest code

KMS does work but X doesn't start

Created attachment 134326 [details]
Dmesg

Created attachment 134327 [details]
Xorg.0.log

Created attachment 135973 [details]
Dmesg

Created attachment 135974 [details]
Xorg.0.log

Looks like X starts now with the drm-next-4.16-wip branch

There's still an error in the logs:

[    0.604111] [drm] amdgpu: dpm initialized
[    0.605298] [drm] Found UVD firmware Version: 1.64 Family ID: 9
[    0.605737] [drm] Found VCE firmware Version: 50.10 Binary ID: 2
[    0.606558] [drm] DC: create_links: connectors_num: physical:3, virtual:0
[    0.606596] [drm:construct] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:1!
[    0.606606] [drm] dal_graphics_object_id_is_equal: Warning: comparing invalid object 'id2'!
[    0.609069] [drm] Display Core initialized!
[    0.642428] [drm] dc_link_detect: manufacturer_id = 2D4C, product_id = C00, serial_number = 1000601, manufacture_week = 42, manufacture_year = 24, display_name = SAMSUNG, speaker_flag = 1, audio_mode_count = 3
[    0.642444] [drm] dc_link_detect: mode number = 0, format_code = 1, channel_count = 1, sample_rate = 7, sample_size = 7
[    0.642454] [drm] dc_link_detect: mode number = 1, format_code = 2, channel_count = 5, sample_rate = 7, sample_size = 80
[    0.642464] [drm] dc_link_detect: mode number = 2, format_code = 7, channel_count = 5, sample_rate = 4, sample_size = 192

I'll check drm-next and Linus's branches when I get home so we can hopefully revert the kabini disablement on DC

What physical display connectors are actually on the board?

I've just checked https://www.computeruniverse.net/en/products/90526096/acer-aspire-xc-105.asp

It has HDMI and a VGA connector, I've only ever used the HDMI connector

Whilst I still get the following message:

[    0.583506] [drm:construct] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:1! type 0 expected 3

DC does now work on Kabini, so can the following revert be applied

Created attachment 136924 [details] [review]
Revert of the Kabini DC disablement

I can send this to the list, though happy for you just to apply it

Poke: this should be reverted, as mentioned in IRC enabling DC has unfortunately broken the displays on this TONGA GPU as well. GPU info:

[AMD/ATI] Tonga PRO [Radeon R9 285/380] [1002:6939] (rev f1)

more info https://people.freedesktop.org/~lyudess/archive/06-24-2018/4.17-rc-breaks-lyude-machine.txt

(In reply to Lyude Paul from comment #13)
> Poke: this should be reverted, as mentioned in IRC enabling DC has
> unfortunately broken the displays on this TONGA GPU as well. GPU info:
> 
> [AMD/ATI] Tonga PRO [Radeon R9 285/380] [1002:6939] (rev f1)

Tonga is a different generation of display hardware so is unrelated to this.

Closing