5K iMac retina multi stream display port

[Dave Airlie]

On 4 October 2015 at 21:36, Andreas Tunek <andreas.tunek at gmail.com> wrote:
> 2015-10-04 13:31 GMT+02:00 Andreas Tunek <andreas.tunek at gmail.com>:
>> 2015-10-04 13:26 GMT+02:00 Andreas Tunek <andreas.tunek at gmail.com>:
>>> 2015-10-04 6:31 GMT+02:00 Dave Airlie <airlied at gmail.com>:
>>>> On 3 October 2015 at 04:03, Andreas Tunek <andreas.tunek at gmail.com> wrote:
>>>>> Hi
>>>>>
>>>>> I sort of recall that somebody (Dave Airlied) work on this in order to
>>>>> get the full 5K from a retina iMac. Was that work finished or is that
>>>>> coming in 4.3 or later? Or was it abandoned? Or maybe I am not
>>>>> remembering correctly?
>>>>
>>>> you can try a 4.2 kernel with radeon.mst=1
>>>>
>>>> I've no idea if it will work.
>>>
>>> Didn't seem to have any effect. Is this a correct boot env:
>>> [
>>> root at iMacLinux tuna]# cat /proc/cmdline
>>> BOOT_IMAGE=/vmlinuz-4.2.1-300.fc23.x86_64
>>> root=UUID=e3e65337-b654-495f-b7c1-0212e1fd0797 ro rhgb quiet
>>> LANG=en_US.UTF-8 radeon.mst=1
>>>
>>>>
>>>> Dave.
>>
>> Sorry for replying again, but you wrote some stuff in February*, did
>> you test with an iMac or some other 5K screen then?
>>
>> http://thread.gmane.org/gmane.comp.video.dri.devel/124345
>>
>> Best regards
>> Andreas

No I never tested anything on an imac 5K.

Can you boot with drm.debug=6 radeon.mst=1 and post the
dmesg logfile?

I'm not sure if the 5K mode on these would need to be reverse engineered
there is definitely some trickery involved.

Dave.