randr: Virtual monitor not present with MST display

[Paul Menzel]

Dear Harry,


On 18.03.19 21:55, Wentland, Harry wrote:
> On 2019-03-08 4:11 a.m., Michel Dänzer wrote:
>> On 2019-03-06 5:35 p.m., Paul Menzel wrote:
>>> On 03/06/19 15:55, Michel Dänzer wrote:
>>>> On 2019-03-06 1:41 p.m., Paul Menzel wrote:
>>>>> On 03/05/19 20:07, Alex Deucher wrote:
>>>>>> On Tue, Mar 5, 2019 at 1:16 PM Paul Menzel wrote:
>>>>>
>>>>>>> Using the MST display Dell UP3214Q (two panels) with an AMD system,
>>>>>>> the virtual monitor object is not created. GDM and Xfce consider both
>>>>>>> panels as separate screens (`xrandr --listmonitors`).
>>>>>>>
>>>>>>> [...]
>>>>>
>>>>> I didn’t provide the output of xrandr in my previous message.
>>>>>
>>>>>      $ xrandr --listmonitors
>>>>>       Monitors: 2
>>>>>       0: +DisplayPort-9 1920/698x2160/392+0+0  DisplayPort-9
>>>>>       1: +DisplayPort-10 1920/698x2160/392+1920+0  DisplayPort-10
>>>>>
>>>>> Please find the X.Org X Server log attached.
>>>>>
>>>>>>> With an Intel system, the monitor object is shown.
>>>>>
>>>>> To clarify, the modesetting driver is used with the Intel hardware.
>>>>
>>>> Does this work better with the modesetting driver on the AMD system?
>>>
>>> With Linux 4.19.19, there was the same problem with the modesetting driver
>>> during my limited testing.
>>>
>>> Updating to Linux 4.20.13, it worked with the modesetting driver, but the
>>> AMDGPU driver still failed to properly utilize the MST monitor.
>>
>> Does
>> https://gitlab.freedesktop.org/xorg/driver/xf86-video-amdgpu/merge_requests/32
>> help?
> 
> Michel, do you know if this is supposed to work with
> xf86-video-amdgpu? When I've tried it before I didn't have any luck but
> didn't have time to look into it.

Sorry, what is your question. With the commit from the merge request 
applied it works here. Also, the commit was added to the master branch 
in the mean time.


Kind regards,

Paul