[RndTbl] recommendations for 4k video card under Linux

Trevor Cordes trevor at tecnopolis.ca
Sat Apr 7 01:19:32 CDT 2018


On 2018-04-06 Gilles Detillieux wrote:
> Hi. Does anyone on the list have experience and recommendations on
> how to support a 4k monitor under Linux? We want to use a single Dell

Hi, I mentioned at a MUUG meeting roundtable last year that I had
picked up a "2k" (2560x1440) monitor and card and got it working.  All
my research and picks apply to 4k also, so my results might be useful to
you.

First off, you want DP.  2k is hard with HDMI, and 4k is doubly so.
Many cards (especially cheaper/older ones) may claim to do high rez's
but their HDMI out port won't, as it's not a new enough spec.  From
memory, you need something like 1.6 instead of 1.4 or whatever (can find
online) but good luck finding out precisely what the HDMI port on your
card actually is from the Taiwan Inc websites.

Same thing applies to cables, for 4k you'll probably need a newest-gen
cable, and they are equally as hard to deduce precisely what version
they are!  DP doesn't suffer from this problem on either front.  If you
get a DP card that says it does 4k, it does 4k, guaranteed, and the
cables are basically all 4k supporting unless you find something really
old.

I tried about 4 different combos of card and 2k monitor before finally
getting something to work, so I'm pretty sure I've figured out the
cheapest (nvidia) way.  And when things aren't going to work, they just
don't work.  You're just stuck at the lower rez with no option to go
higher and no hint as to why.  I suppose you could probably get things
working at lower clocks using xorg.conf modelines like the bad 'ol
days, but I didn't want to delve there.  When you get the right parts
it all "just works".

The cheapest card that I could find that would support 4k and DP and
vdpau (important for me) was the GTX 1050.  Any 1050 with DP out should
be A-OK.  I sell them for just over $200, but I'm sure there are deals
elsewhere out there.

I'm not 100% positive but I think when I first booted up with my
nouveau drivers they didn't work and it fell back to fb or vesa or
something.  That was 1 year ago.  Eventually nouveau will support the
1050, maybe already does.  The chipset codename according to lspci is
GP107 if that helps.

No whoop, I switch between nouveau and nvidia binaries frequently when
FLOSS support catches up with the technology.  "Updating kernel ate my
nv binary" hasn't been a concern for me for at least 5 years now.  If
you're using Fedora, just use the rpmfusion nvidia and (a|)kmod-nvidia
rpms and every time you dnf update the kernel the binaries auto-compile
and you have to do zero additional steps when you reboot.  It just
keeps working.  (And it bypasses having to wait for the repo guys to
update the non-akmod rpm version which always takes 1-2 weeks!)

One caveat: after the dnf update finishes, wait about 2 minutes for the
gcc processes to finish compiling or you'll be foobar until you run
akmod --somethingorrather from a single boot. (Nothing at all indicates
you need to wait after an update before rebooting.)

I'm probably stuck with binaries for a long time as I really like vdpau
now and I'm pretty sure that won't be in the FLOSS drivers for many
more years, if ever.  The binaries are pretty good.  No stability
issues, though sometimes there's little cosmetic glitch bugs that they
eventually hammer out in updates (I currently have zero of these
occurring).  The only sucky part is if you want to bisect/debug for the
LKML guys (which I seem to do way too often lately) you'll need to
reproduce your bug in non-tainted before posting your results.

My monitor is also a Dell (2k) and it's great.  Their quality/price
ratio can't be beat on mid/high-end monitors.  I sell quite a few and
can often get amazing prices on Dell LCDs through my suppliers, so if
you're in Wpg give me a shout.

My next project is to try the DP daisychain feature as I want 2 x 2k
LCD instead of my current 2k + 1600x1200.  And I'm not convinced the
1050's HDMI will do 2k or 4k so daisychain might be the only option.
(My big q is can a non-daisy LCD daisy off a has-daisy LCD or do both
need to be daisy-capable, i.e. with passthru.)  If a 2nd 2k/4k monitor
is in your future give the daisy port yes/no feature serious
consideration before you buy your first one.  No "affordable" card I
looked at had dual DP out.

I'll end with a quick note about 2k vs 4k.  I thought long and hard
about which to buy, as the price diff was sub-$200.  I went with 2k as
I do almost zero graphics/images and I realized that for my workload,
normal daily desktop use + 90% cmd line and programming work, 4k would
buy me nothing.  In fact, besides graphics work I can't see any use for
4k.  My goal is always the most usable real estate, and with 2k on a
24" I was able to vastly increase my pixel count yet keep all my
working terminal font sizes constant at 9 pixel mono terminal font.

I guess what I'm saying (and I'm sure you've already thought about it)
is don't just say "ooooh 4k" and get that, think about what you are
really trying to achieve.  The other upshot of picking 2k, besides
price, is that you can go 2 x 2k fairly easily on most cards, but 2 x
4k might go beyond the $200 cards' max overall screen dimensions.

Good luck!  And if you ever daisychain, let me know.


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