Source
r/linuxquestions•
atzero

1440p Over HDMI. Works in Windows, not Linux

Okay so as the title says, I've got a 1440p monitor that I'm trying to get running at native resolution but on the Linux end, I'm having trouble. Windows displays it just fine.

System:

i5 9400f

Vega 56 gpu

2560x1440@60 Monoprice monitor (generic Korean panel), adapting DVI-D to HDMI.

OS: Antergos (although Kubuntu had the same problem)

So far, I've tried:

  • xrandr wasn't listing the correct resolution, so I use cvt to generate modelines 2560x1440_60, 2560x1440_55, 2560x1440_30, 2560x1440_24, then used the generated modes using "xrandr --newmode", then added them using "xrandr --addmode".
  • They appear to be configured correctly and are now shown in xrandr, but "xrandr --output" fails and reverts after the screen goes black.
  • I've tried to use the Windows application Powerstrip to find whatever Windows is using for the modelines, but the option to look at them is grayed out, so sadly I can't compare modelines between the OS's.

Any advice?

Posted Apr 11, 2019, 7:55 AM UTC

56
grumbel•

Have a look at /var/log/Xorg.0.log, see if the 2560x1440 mode gets rejected for some reason. Also try:

sudo get-edid | parse-edid

And see if that can output a modeline. If that doesn't help, start randomly trying modelines found online, e.g.:

Modeline 	"Mode 12" 241.50 2560 2608 2640 2720 1440 1443 1448 1481 +hsync -vsync

I never really had much luck with doing it systematically or trying to convert Windows modelines, but random modelines found online do sometimes work.

3
atzeroOP•

Awesome, thanks! I'll give it a shot.

2
atzeroOP•

Hmm, no dice. get-edid just errors on me and I can't seem to find a modeline that xrandr likes. Further complicating things, I read through a thread which suggested that the dual link dvi wasn't being supported anymore and the person that got a fix going basically did so by modifying the Linux kernel. Sadly above my skill set.

xorg.0.log is giving me:

[ 2340.073] (II) AMDGPU(0): => pitch 17920 bytes

[ 2340.121] (EE) AMDGPU(0): failed to set mode: Invalid argument

[ 2357.623] (EE) client bug: timer event3 debounce short: offset negative (-7ms)

+[ 2372.706] (EE) AMDGPU(0): failed to set mode: Invalid argument

+[ 2372.741] (EE) AMDGPU(0): drmmode_do_crtc_dpms cannot get last vblank counter

+[ 2372.774] (EE) AMDGPU(0): drmmode_do_crtc_dpms cannot get last vblank counter

2
benbrockn•

Just curious, could it be the adapter causing issues?

3
emican•

Came here to make the same comment. Adapters have caused issues for me in the past on nvidia cards.

2
atzeroOP•

It's certainly possible, but I'm kind of thinking it's more a driver issue since it works fine in Windows. My guess is using dual-dvi spec over hdmi is a feature that was too niche to support. Hell, even when I updated my AMD graphics driver, it wouldn't see past 1080p in Windows. Reverting my drivers fixed it but that's not how I'm going to proceed. I just bought a new DP supporting monitor so that'll "fix" the problem.

1