Can't select 2560x1440 resolution even though I know it's possible (I have proof!)

Question

I have a new monitor, (the Dell U2515H) which I'm trying to drive at 2560x1440 resolution (just 30hz) over HDMI using only the onboard graphics on my machine (Intel HD4000 found in the ivy bridge CPU). My exact machine spec here.

I know it's possible because I've had it working once yesterday and once today. It just randomly appeared in my available screen resolution options. Yesterday it worked for a bit (~10 minutes?) then suddenly flipped back to 2048x1152 and the option for 1440 resolution disappeared. Today the option appeared and so I selected 2560x1440 which worked fine:

I then tried re-booting the machine in an effort to "persist" my preference, but after rebooting I hit this error message:

Full error message here if anyone is interested, but basically, it looks like it never tried 30hz.

On the right hand side of the screenshot you can see the output from xrandr so you can see that my option for 2560x1440 has disappeared again.

I've tried using xrandr to add the resolution manually but it doesn't work:

matt@beast:~$ gtf 2560 1440 30

  # 2560x1440 @ 30.00 Hz (GTF) hsync: 43.95 kHz; pclk: 146.27 MHz
  Modeline "2560x1440_30.00"  146.27  2560 2680 2944 3328  1440 1441 1444 1465  -HSync +Vsync

matt@beast:~$ xrandr --newmode "2560x1440_30.00"  146.27  2560 2680 2944 3328  1440 1441 1444 1465  -HSync +Vsync
matt@beast:~$ xrandr --addmode HDMI2 "2560x1440_30.00"
matt@beast:~$ xrandr --output HDMI2 --mode "2560x1440_30.00"

(screen flicks black for a moment but it just doesn't change the mode).

Any ideas what I can try next?

---

Update

I was able to get the edid information (thanks to the kind author of get-edid):

Section "Monitor"
        Identifier "DELL U2515H"
        ModelName "DELL U2515H"
        VendorName "DEL"
        # Monitor Manufactured week 45 of 2014
        # EDID version 1.3
        # Digital Display
        DisplaySize 550 310
        Gamma 2.20
        Option "DPMS" "true"
        Horizsync 30-113
        VertRefresh 56-86
        # Maximum pixel clock is 300MHz
        #Not giving standard mode: 1680x1050, 60Hz
        #Not giving standard mode: 1920x1200, 60Hz
        #Not giving standard mode: 1152x864, 75Hz
        #Not giving standard mode: 1600x1200, 60Hz
        #Not giving standard mode: 1280x1024, 60Hz
        #Not giving standard mode: 1200x960, 60Hz

        #Extension block found. Parsing...
revnum: 3
        Modeline        "Mode 16" 148.50 1920 2008 2052 2200 1080 1082 1087 1125 +hsync +vsync
        Modeline        "Mode 0" 241.50 2560 2608 2640 2720 1440 1443 1448 1481 +hsync -vsync
        Modeline        "Mode 1" 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
        Modeline        "Mode 2" 74.250 1920 2008 2052 2200 1080 1082 1087 1125 +hsync +vsync interlace
        Modeline        "Mode 3" 74.250 1280 1390 1420 1650 720 725 730 750 +hsync +vsync
        Modeline        "Mode 4" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
        Modeline        "Mode 5" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
        Modeline        "Mode 6" 27.027 1440 1478 1602 1716 480 484 487 525 -hsync -vsync interlace
        Modeline        "Mode 7" 27.000 1440 1464 1590 1728 576 578 581 625 -hsync -vsync interlace
        Modeline        "Mode 8" 25.200 640 656 752 800 480 490 492 525 -hsync -vsync
        Modeline        "Mode 9" 74.250 1920 2448 2492 2640 1080 1082 1089 1125 +hsync +vsync interlace
        Modeline        "Mode 10" 148.500 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
        Modeline        "Mode 11" 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
        Modeline        "Mode 12" 74.250 1280 1720 1760 1980 720 725 730 750 +hsync +vsync
        Modeline        "Mode 13" 74.250 1920 2558 2602 2750 1080 1084 1089 1125 +hsync +vsync
        Modeline        "Mode 14" 74.250 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
        Modeline        "Mode 15" 74.250 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
        Modeline        "Mode 17" 74.25 1920 2008 2052 2200 540 542 547 562 +hsync +vsync interlace
        Modeline        "Mode 18" 74.25 1280 1390 1430 1650 720 725 730 750 +hsync +vsync
        Modeline        "Mode 19" 27.00 720 736 798 858 480 489 495 525 -hsync -vsync
        Option "PreferredMode" "Mode 16"
EndSection

It looks like the mode I want is "Mode 0" so I tried to set that using xrandr (was that the correct thing to do?) but it doesn't seem to work:

matt@beast:~$ xrandr --newmode "2560x1440_47.43"  241.50  2560 2728 3000 3440  1440 1441 1444 1480  -HSync +Vsync
matt@beast:~$ xrandr --addmode HDMI2 "2560x1440_47.43"
matt@beast:~$ xrandr --output HDMI2 --mode "2560x1440_47.43"
xrandr: Configure crtc 0 failed

I can see the 2560x1440 option in "Screen Display" settings but I just get this error message:

Now what can I try?

Solution

Another answer that was also posted here earlier was correct.

Before I start let me say that I have no problem on my Haswell setup with a CS1794 KVM switch and a 2m HDMI cable (ASIN: B003L1ZYYM) connected to the U2515H.

HDMI2 connected 2560x1440+4480+0 (normal left inverted right x axis y axis) 553mm x 311mm
   2560x1440      60.0*+
   1920x1080      60.0 +   60.0     50.0     59.9     30.0     25.0     24.0     30.0     24.0
…

It's a bit different on my Ivy Bridge setup with the same equipment, but I can configure 24Hz and 30Hz modelines with gtf:

xrandr --newmode "2560x1440_24.00"  114.37  2560 2648 2912 3264  1440 1441 1444 1460  -HSync +Vsync
xrandr --addmode HDMI2 "2560x1440_24.00"
xrandr --output HDMI2 --mode "2560x1440_24.00"

xrandr --newmode "2560x1440_30.00"  146.27  2560 2680 2944 3328  1440 1441 1444 1465  -HSync +Vsync
xrandr --addmode HDMI2 "2560x1440_30.00"
xrandr --output HDMI2 --mode "2560x1440_30.00"

And this is what my xrandr output looks like:

HDMI2 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 553mm x 311mm
   2560x1440      30.0*+
   2048x1152      60.0
   1920x1200      60.0
   1920x1080      60.0     60.0     50.0     59.9     30.0     25.0     24.0     30.0     24.0
   1920x1080i     60.1     50.0     60.0
   1600x1200      60.0
   1680x1050      59.9
   1280x1024      75.0     60.0
   1200x960       60.0
   1152x864       75.0
   1280x720       60.0     50.0     59.9
   1024x768       75.1     60.0
   800x600        75.0     60.3
   720x576        50.0
   720x576i       50.1
   720x480        60.0     59.9
   720x480i       60.1     60.1
   640x480        75.0     60.0     59.9
   720x400        70.1
   2560x1440_30.00   30.0
   2560x1440_24.00   24.0

24Hz refresh rate is as low a you can go and it feels terrible, 30Hz is just a little bit of improvement. You should get a proper HDMI 1.4 or DisplayPort setup. Even DisplayLink adapters would be worth looking into after they have finally published Linux drivers for their USB 3.0 devices.

Comments

[Admin]

It looks like our screen cannot support the signal reliably. Xrandr will only report resolutions that both screen and gfx cards can accept together.

[Admin]

You could manually specify the resolution in /etc/X11/xorg.conf but it doesn't mean that the driver will agree with it.

[Admin]

Another strong possibility is that your hdmi cable cannot cope with the throughput, try a certified cable (there doesn't seem to be much complaints about your screen, so it looks like a better guess).

[Admin]

@didierc would it still be possible that the fault is the cable even though it has previously worked for 10 minutes? (no markings on cable unfortunately)

[Admin]

Yes, totally possible: I suppose that in certain specific — optimal — conditions the cable can work (like an overclocked CPU), but ootherwise it will not.

[Admin]

I understand though that you'd like to have all the guarantees before proceeding to buy a new cable, but I cannot provide more. I suggest you get in touch with either Dell or Intel to discuss replacement for either product, if you feel one is 'being faulty, but surely they will first advise you to try a certified cable.