On Thu, 12 Aug 2021 17:45:47 -0500, o1bigtenor wrote in message
<CAPpdf58=D9FiRP98yAnNp5xSE+rODp9yUypugVkdvKLz6vqjRA@???>:

> Greetings
>
> I am running a fairly old rig on debian testing with 2 gpus

..which gpus, and which drivers?
IME, my old gpus runs better with nouveau and radeon.

> and want to run 5 monitors.

..that rig should be fun on flightgear(.org). ;o)

> The 5th is hdmi connected and is a 4k monitor with the other 4 all
> being 1920x1080.
> After I installed the 4k monitor I had regular graphics sub-system
> freezes (won't come out of suspend typically) with a normal being a
> system reboot at least once every 24 hours.

..tried keeping a ssh session going into it? Graphics
sub-system freezes shouldn't kill ssh nor networking.

> I filed a bug report. Have subsequently unplugged the 4k monitor - -
> - - a lot of headache rebooting and setting up the machine at least
> 1x per day.
>
> Recommendation is to download and install even a 5.14 (still in beta)
> kernel.
>
> The newest kernel (changed just yesterday) for debian in debian
> experimental is a 5.13.?? version.

..debian tradition before the systemd coup, used to call stable
things upstream, "experimental." Todays kernel list:
arnt@d44:~$ siste-kernels

   mainline:   5.14-rc5      2021-08-08
   stable:     5.13.10       2021-08-12
   stable:     5.12.19 [EOL] 2021-07-20
   longterm:   5.10.58       2021-08-12
   longterm:   5.4.140       2021-08-12
   longterm:   4.19.203      2021-08-12
   longterm:   4.14.243      2021-08-08
   longterm:   4.9.279       2021-08-08
   longterm:   4.4.280       2021-08-10
   linux-next: next-20210813 2021-08-13

Other resources
Fri Aug 13 12:36:32 CEST 2021
arnt@d44:~$

..catch your own updated list with e.g.:
arnt@d44:~$ alias siste-kernels
alias siste-kernels='lynx -dump -width 144 https://www.kernel.org/ \
|grep -A 14 "Latest Release" |tail -n 13 |cut -c -40 ;date '
arnt@d44:~$

> Dunno if I want to try a beta kernel (sorta scared to in fact).

..then make it boring with Devuan's good old Debian way, add your
build tree to your /etc/apt/sources.list, and install your .debs
from your local build tree with e.g. aptitude.
Will even do all the bootloader updating automagically.

> Suggestions from y'all?
> (Y'all, or at least quite a number of you, have a lot more experience
> at this than I do.)

..err, guys, has Devuan's good old Debian way changed in any way the last
dozen years?
We of course disabled systemd and use a real init, or did we just leave
it the way it was, leaving out Debian's nice shiny new barn door?


> Please advise.

..pick 5.13.10 and build and install it Devuan's good old Debian way.

..if that kernel fails, chk for 5.13.11 etc, if those fail, your rig
might be "too old", so fall back to try 5.10.58 or whatever the next
version there is. Etc down the longterm trees.

--
..med vennlig hilsen = with Kind Regards from Arnt Karlsen
...with a number of polar bear hunters in his ancestry...
Scenarios always come in sets of three:
best case, worst case, and just in case.