Hi Andreas--
lspci shows this:01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cape Verde GL [FirePro W4100]which shows the Cape Verde but not the Southern Island.  I think all Cape Verde are that, though.

The old radeon kernel module paired with the Xorg radeon driver is the one that gives random annoying flashes. I can almost live with them, but under virtualbox win7 which my wife runs once a week it is unbelievably flashy!
The newer amdgpu module fails to work with the Xorg amdgpu driver.  This is with ascii, beowulf, and kernels 4.9, 4.19, and 5.4.  I'm able to get them installed, they just won't start.  The Xorg amdgpu version is 18.1, from late 2018, and a 19.1 is out, from 2019, but claims only minor tweaks.  I'm not thinking it's worth bothering to try to compile that.
I'm pretty sure Roland is the biggest expert here on this card!  A hardware issue with timing could be there.  Interestingly enough a similar ASRock motherboard to mine was used in online benchmarks for this card.  That certainly doesn't prove that my motherboard would work with it, just that I'm not completely crazy ;)
--Tim

    On Saturday, February 1, 2020, 4:16:53 PM UTC, Andreas Messer <andi@???> wrote:  

On Fri, Jan 31, 2020 at 11:03:24AM +0000, R. G. Sidler wrote:
>
> Hi Tim, Ludovic and Andreas.
>
> I installed only the amdgpu-driver. Since I always start with a naked
> base install, I never care about blacklisting any drivers, because I
> just don't install them 😉

Well, the drm (nvidia/amd/..) kernel modules are all installed with
a single kernel package so you can only decide which to install by
building your own kernel package. Blacklisting is the only way to force
them not to load. But I assume you know that, since you're using
Debian/Devuan already :)

Maybe another thing: Since the W4100 seems to use the Cap Verde /
Souther Island GPU kind (Can you confirm this, using lspci -l e.g.?) you
have the option of using two different kernel drivers with a recent
linux kernel:

- radeon: this is the older/mature one (the default one)
- amdgpu: this is the newer one which might have flaws with SI chipset

You can choose them by setting some kernel module parameters (I did this,
through /etc/default/grub recently to try something)

And maybe a clarification: The graphics driver is divided into two parts:
the kernel module and the xorg driver. The xorg driver in beowulf should
be able to play with both kernel drivers, I think the amd proprietary xorg
driver only works with the amdgpu kernel module.

> @Andreas I decided to install a dedicated AMD workstation graphics card,
> since I only do workstation stuff on my Thinkstation 😉
>
> I prefer a very stable signal over high performance.

Did you observe any difference? I mean, the transmission of data between
graphics card and display should be digital nowadays. (I owned a FireGL2
a long while ago but remind only the negative aspects of it)

cheers
Andreas_______________________________________________
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