If external monitor is set vertical, display becomes choppy.

Quardah · 2022-10-24 20:05:09

Hi. This is a followup to this thread but i'm making a new for clarity : https://bbs.archlinux.org/viewtopic.php?id=280164

I have a laptop (2560x1600) with an external monitor (1920x1080). I want the external to be vertical on the right. This was running fine until some updates mid september.

Regardless of which desktop environment i am running (behavior is the same with Budgie or KDE), if the monitor is set vertical (90 degrees or 270 degrees) using KDE's display settings, the whole system goes 30fps. Everything is choppy. I do not have the same problem if the monitor on the right is kept at a landscape configuration.

I am running on a P16s with AMD Pro 6850u integrated.

Could it be because in latest mode-setting driver does not support 3640x1920 (2560+1080 width with 1920 height) displaying at 60hz so it falls back to 30hz? I recall this setup was functioning correctly on my T540p (with 3K screen 2880x1620) running intel integrated on Debian, i find it quirky that i am getting such a behavior on such a newer platform.

xrandr mentions both output at 60hz, and the external monitor OSD also mentions getting a 60hz signal. But the system is 30hz absolutely because all animations are slowed. I recall i did not have this behavior when i installed arch about three months ago, it has to be a software update causing this.

In the other thread i mentioned i had better performances not using the usb-c hub but instead using the laptop port but after all it is not the case, regardless of using the laptop's HDMI or hub's HDMI i have the degraded performances.

Thanks.

seth · 2022-10-24 20:37:12

Check the performance level, https://wiki.archlinux.org/title/AMDGPU#Overclocking
At least nvidia GPUs move into performance mode when transforming the output.

Quardah · 2022-10-25 18:47:39

Yea thanks for the response but i would rather not do that to be honest. The laptop is brand new, it's the latest platform available. It certainly isn't a lack of performance; it was working ok 2 months ago.

It has to be software related somewhere.

If i run 2048*1536 with the external monitor i do not get the performances drop.

It's some config issue somewhere with the updated package. Has to be.

EDIT1: I tried some things. Trying Linux-LTS instead didn't give me much, the display is unstable completely. Plus it breaks wi-fi, and even rebooting in latest kernel makes the wireless card not functional. I had to purge linux-lts en make grub config anew for it to work again.

Also i notice that if the external monitor is connected on boot, i get a smooth 60Hz in SDDM login screen while both resolutions are at maximum. It's only once logged into the session during the splash loading screen that it goes out and comes back in momentarily and i start getting 30Hz. Note that if i downsize the internal to 1680x1050 with the external attached i get 60Hz back, or if i set my external landscape and not vertical i can get smooth 60Hz at full resolution.

This problem is very silly and it legit kills my experience -_-

Last edited by Quardah (2022-10-25 19:45:28)

seth · 2022-10-25 19:48:03

I'm not asking you to overclock the system but check the performance state it enters (the wiki indicates where to look for that)

Quardah · 2022-10-25 23:54:22

seth wrote:

I'm not asking you to overclock the system but check the performance state it enters (the wiki indicates where to look for that)

Ok i see.

When running the command to "manually check the P-state" i get the following :

[myuser@P16s ~]$ cat /sys/class/drm/card0/device/pp_od_clk_voltage
OD_SCLK:
0:        200Mhz
1:       2200Mhz
OD_RANGE:
SCLK:     200Mhz       2200Mhz

but for some reason i tried some other things and i can get the system to work at proper resolution with 60hz if i turn off the monitor in KDE's display configuration (uncheck "enabled") and then reenabling it.

If i reboot, it goes back to choopy 30Hz until i do the same thing again.

I have absolutely no idea what to do with this to permanently fix this problem. I'd just like the damn thing to work.

Last edited by Quardah (2022-10-26 01:18:41)

seth · 2022-10-26 08:08:08

but for some reason i tried some other things and i can get the system to work at proper resolution with 60hz if i turn off the monitor in KDE's display configuration (uncheck "enabled") and then reenabling it.

Race condition?
Is the compositor relevant to this situation (ie. does restarting it w/ SHIFT+Alt+F12 achieve the same)?
Do you rotate the output w/ kscreen and the session configuration or an xorg configlet or the DM?

Quardah · 2022-10-27 01:37:37

Hi. It seems like SHIFT + ALT + F12 does nothing even though i can see it bind as a keyboard shortcut. I rotate the output exclusively in KDE's systemsettings where i set the external to be rotated 90 degrees.

It seems to be doing great now. What i did since it was last broken was

1 - Install linux-lts
2 - grub-mkconfig
3 - try booting with linux-lts, garbage output everywhere, plasma crashed, nothing worked as expected
4 - boot into normal linux, purged linux-lts, grub-mkconfig again
5 - reboot with only normal linux

it was choopy 30hz again. i switched off the external monitor, changed the internal monitor's resolution to 1680x1050 and turned on the external afterwards. I was getting stable 60hz. i then tried going for 2560x1600 on internal and everything has been working fine since.

i am not rebooting, not until i am done with something i must do before the weekend. but i'm telling you all in case someone else has a similar issue or in case it helps with debugging.

also i did try budgie instead of KDE. got the same result. i then purged KDE to run only budgie but changing the themes would make budgie crash so i just abandoned the idea of changing DE, plus purging KDE removed all the kool KDE apps (i legit love KDE). so i reinstalled KDE and everything came back as it was.

Maybe this operationg fixed something somewhere. I don't know. as i am writing this right now the system works perfectly as expected, but i am certain if i reboot i will lose this stability. I changed my resolution once to 2048x1536 to play my old legacy game and changed back to 2560x1600 and it's still working, so it seems like the system unfucked itself at some point through these manipulations.

seth · 2022-10-29 13:02:04

1-5 is idenmpotent, you restored the status quo ante (resulting in the status quo ante ;-)

i switched off the external monitor, changed the internal monitor's resolution to 1680x1050 and turned on the external afterwards. I was getting stable 60hz. i then tried going for 2560x1600 on internal and everything has been working fine since.

If we assume somewhat random behavior and assume that the driver tries to sync to both outputs and assume that depending on when the outputs are activated their vblank signal can be shifted by 8ms and so rendering at 60fps (16ms interval) would effectively skip every other frame.
Do you have https://wiki.archlinux.org/title/AMDGPU … _rendering on and did you try to turn it off (and then reproduce the issue)?

Edit: https://wiki.archlinux.org/title/AMDGPU … ut_latency

Last edited by seth (2022-10-29 13:03:10)

Quardah · 2022-10-31 18:09:43

seth wrote:

1-5 is idenmpotent, you restored the status quo ante (resulting in the status quo ante ;-)
i switched off the external monitor, changed the internal monitor's resolution to 1680x1050 and turned on the external afterwards. I was getting stable 60hz. i then tried going for 2560x1600 on internal and everything has been working fine since.
If we assume somewhat random behavior and assume that the driver tries to sync to both outputs and assume that depending on when the outputs are activated their vblank signal can be shifted by 8ms and so rendering at 60fps (16ms interval) would effectively skip every other frame.
Do you have https://wiki.archlinux.org/title/AMDGPU … _rendering on and did you try to turn it off (and then reproduce the issue)?
Edit: https://wiki.archlinux.org/title/AMDGPU … ut_latency

Hi. Sorry for the late reply i just saw your message.

I came back because i figured something out :

If i enable the external monitor as vertical and its highest point is higher than the build-in screen (like this : https://i.imgur.com/K6adL3J.png ) it drops to 30hz.

If i enable the external monitor as vertical with it's highest line matches the build-in screen (like this : https://i.imgur.com/dO2yYo5.png ) i get smooth 60hz. From that point i can set it like the example above (raise the external display to center it) and i keep the 60hz refresh rate.

I will try your config file but before i'd like to ask if you think the pageflip option will have any effect because i read in the driver's doc : https://man.archlinux.org/man/extra/xf8 … mdgpu.4.en that Option "EnablePageFlip" "boolean" only affects when running DRI2 which is not the default unless running an old version of X and i'm running latest X 21.1.4-1

I will absolutely try forcing the TearFree doe.

seth · 2022-11-01 12:49:21

I don't expect any impact from pageflip settings, the second link was to illustrate the tearfree setting.

seth · 2022-11-04 13:28:17

https://cgit.freedesktop.org/xorg/xserv … 4246a1e114 might be interesting.

Arch Linux

#1 2022-10-24 20:05:09

If external monitor is set vertical, display becomes choppy.

#2 2022-10-24 20:37:12

Re: If external monitor is set vertical, display becomes choppy.

#3 2022-10-25 18:47:39

Re: If external monitor is set vertical, display becomes choppy.

#4 2022-10-25 19:48:03

Re: If external monitor is set vertical, display becomes choppy.

#5 2022-10-25 23:54:22

Re: If external monitor is set vertical, display becomes choppy.

#6 2022-10-26 08:08:08

Re: If external monitor is set vertical, display becomes choppy.

#7 2022-10-27 01:37:37

Re: If external monitor is set vertical, display becomes choppy.

#8 2022-10-29 13:02:04

Re: If external monitor is set vertical, display becomes choppy.

#9 2022-10-31 18:09:43

Re: If external monitor is set vertical, display becomes choppy.

#10 2022-11-01 12:49:21

Re: If external monitor is set vertical, display becomes choppy.

#11 2022-11-04 13:28:17

Re: If external monitor is set vertical, display becomes choppy.

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