[RndTbl] recommendations for 4k video card under Linux

[Gilles Detillieux]

On 2018-04-28 04:47, Trevor Cordes wrote:
> On 2018-04-23 Gilles Detillieux wrote:
>> Just a quick follow-up on how things went: really quite smoothly! I
>> never had to change any configuration or install any drivers. It
>> autodetected the new card with no problems. The logs didn't clearly
> You mean you got it working with nouveau?  That means either they fixed
> the 1050 + large monitor support, or I was mistaken and it's because of
> vdpau that I was forced to use nvidia binary.
>
> If you're using nouveau, can you check if it supports vdpau?  (One can
> always dream.)
>
> As for login screens: mine is rotated 90 degrees because of my
> preferred physical rotation. :-)  If I have to mouse something it sure
> makes it challenging.
>
> Thanks for sharing.  Now if someone gets 2 2k or 4k monitors working on
> Linux, that's what we need to hear reported next!  (And if using DP
> daisychain...)

That's the thing. I'm not sure exactly which driver it's using. What I 
wrote last week, partly shown in the context above, was: 'The logs 
didn't clearly show what was going on behind the scenes, just that it 
was now using a "glamoregl" module and glamor OpenGL accelerated driver 
that it wasn't using before. No feedback on detected chipset or anything 
of the sort.' So it "just works", but I don't know how/why exactly. The 
logs make no mention of "nouveau" or "vdpau". With the previous Radeon 
adapter (built-in to the m/b), the logs had a line that said "(II) 
RADEON(0): [DRI2]   VDPAU driver: r600", but not with the current video 
card and driver. Now there is a line that says "(II) glamor: OpenGL 
accelerated X.org driver based." That suggests to me that the driver is 
called glamor, and supports hardware acceleration, rather than just a 
simple generic VESA or frame buffer driver, but it's all a bit of a 
black box to me. Performance is good, but I'm not doing anything fancy - 
just fairly static 2D graphics. We wanted the high resolution to display 
lots of signals without losing too much detail.

As for the rotated login screen, I did have to figure that out on a 
different RHEL 7 clone system. (Another lab, that got the video detail 
they needed by sacrificing time resolution on the X axis to gain voltage 
resolution on the Y.) The trick is once you have the display configured 
properly for your login account, you need to copy that to GDM's 
configuration:

     cp /home/<username>/.config/monitors.xml /var/lib/gdm/.config/

On Ubuntu, that directory would be /var/lib/gdm3/.config/ according to 
what I read online. If you have many login usernames that will use that 
rotated monitor, you may want to copy monitors.xml to their ~/.config 
directory too, or they will have to do the monitor configuration 
themselves when they first login.

-- 
Gilles R. Detillieux              E-mail: <grdetil at scrc.umanitoba.ca>
Spinal Cord Research Centre       WWW:    http://www.scrc.umanitoba.ca/
Dept. of Physiology and Pathophysiology, Faculty of Health Sciences,
Univ. of Manitoba  Winnipeg, MB  R3E 0J9  (Canada)