[RndTbl] recommendations for 4k video card under Linux

Gilles Detillieux grdetil at scrc.umanitoba.ca
Mon Apr 9 14:31:09 CDT 2018

Thanks, everyone, for all the advice. It does put my mind at ease that 
nVidia seems to be a safer bet than I had thought. I think we'll give a 
GTX 1050 card a try. We'll likely stick to DisplayPort 1.4, which should 
do 4k without a snag, and avoid the potential headaches of HDMI. Don't 
need 5k, don't need more than 1 monitor so we won't be messing with 
passthrough/daisychain, and won't wait for TB3. ;-)

Gilles (unrepentant top-poster)

On 2018-04-07 11:08, Adam Thompson wrote:
> (Top-posting to save time, sorry)
> You need HDMI 2.1 for guaranteed 5k support.  IIRC, HDMI 2.0 
> guaranteed 4k support.
> When I say "guaranteed", I don't mean "HDMI Assoc. says it'll work", I 
> mean "yes, it's going to work in the real world".
> Hanging a non-passthrough DP monitor off of a passthrough-capable 
> monitor is exactly the use case that feature is designed for.
> I sincerely hope that TB3 takes over as a video cabling standard and 
> finally replaces both DP and HDMI, but I don't really think it'll 
> happen...  in any case a single 40GBps TB3 connection still only 
> supports 1 x 5k or 2 x 4k displays.
> -Adam
> On 2018-04-07 01:19, Trevor Cordes wrote:
>> 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.

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)

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