Awry text after monitor upgrade

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DrCR
Posts: 58
Joined: 30. May 2014, 05:14

Awry text after monitor upgrade

Post by DrCR »

Greetings,

I just upgraded from a flaky venerable 1200p panel to the Samsung Odyssey G7 27" 1440p highrefreshetc. When I booted into my Ubuntu partition for gaming, it seamlessly handled the resolution change, all good.

When I booted into daily driver Salix, the text is awry with serious legibility issues. I don't recall if I'm running off of nouveau or the proprietary Nvidia driver, but I suspect the former since I'm not gaming in Salix. Via TUI or mounting from the Ubuntu install, is there some config file I can delete to attempt a redect? There was at least some sort of auto-detection though, considering the Display area shows 2560x1440. Thoughts?

Photograph:
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Last edited by DrCR on 29. Nov 2020, 10:02, edited 3 times in total.
DrCR
Posts: 58
Joined: 30. May 2014, 05:14

Re: Garbled text after monitor upgrade

Post by DrCR »

Update: For a comparison, via my Ubuntu install I grabbed the SalixLive64 Xfce 14.2.1 DVD ISO, put it on a USB thumbdrive, and booted from it -- same issue.

Photographs of said SalixLive64:
Image Image
DrCR
Posts: 58
Joined: 30. May 2014, 05:14

Re: Awry text after monitor upgrade

Post by DrCR »

Here's some additional photos.

Booting OK initially:
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Becomes awry:
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Becomes very awry. (Reminds me of Hebrew):
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And here's a photo of what I see for rting's chroma-subsampling test image:
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Download full


Note: The cable current being used is a DVI-HDMI. I did not use the DP-DP included with the Samsung Odyssey G7 due to it being too short. But I plan to test if Salix is happy if the DP-DP cable is used.
DrCR
Posts: 58
Joined: 30. May 2014, 05:14

Re: Awry text after monitor upgrade

Post by DrCR »

Working without issue via DP-DP.

Looks like something about the DVI-HDMI cable usage causes Salix to get confused. Since I'm ordering a longer DP-DP cable, the DVI-HDMI is only a stopgap.

So this can be considered a case closed, unless gapan and company wish to look into the matter.
galmei
Posts: 166
Joined: 1. Jun 2018, 21:54

Re: Awry text after monitor upgrade

Post by galmei »

You essentially have a monitor and a computer with at least a dual-boot installation, so why would it be the cable? If it is not the DVI-HDMI cable combination, here are some thoughts.

Whether you use the Nouveau or the Nvidia driver on Salix can be found in the file /var/log/Xorg.0.log If you are fast enough, you can see the message of the driver during the boot (the output can be paused with Ctrl-S and continued with Ctrl-Q, as a gamer you surely have an extraordinary responsiveness).

There may be the configuration file /etc/X11/xorg.conf, alternatively there may be configuration files in /etc/X11/xorg.conf.d. The file 10-keymap.conf there must remain there in any case, otherwise your keyboard will not work anymore or the X server will do the straddle.

One way to find an approach is to compare the two Xorg.0.log from Salix and Ubuntu (do not use diff) and find the main differences where you can start. The only prerequisite is that your Ubuntu installation still uses the X server.

One approach would be to determine if Ubuntu ignores the EDID data of the monitor and Salix uses it instead. EDID is often wrong even with new monitor models. One could get X11/the driver under Salix to ignore this data and use manually created data if necessary. If you manage to detect the drivers used on both systems (Xorg.0.log), you could try to find and install a newer one for Salix.

You have used SalixLive64 Xfce; how does a similarly old version of Ubuntu behave? You can find many more approaches.
DrCR
Posts: 58
Joined: 30. May 2014, 05:14

Re: Awry text after monitor upgrade

Post by DrCR »

galmei wrote: 29. Nov 2020, 13:40You essentially have a monitor and a computer with at least a dual-boot installation, so why would it be the cable? If it is not the DVI-HDMI cable combination, here are some thoughts.
As posted above, the issue is present in Salix but not Ubuntu (18.04) when the DVI-HDMI cable is used. And all is copacetic when a DP-DP cable is used. Why would this be the case? Don't know, but that's what's up.

Thanks for the elaboration re log and config files. /var/log/Xorg.0.log confirms I'm using nouveau for Salix.

gapan/distromaintainers, let me know if you want me to dig into this more, but since I'll be using DP-DP, I'm otherwise moving on.

Best regards
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gapan
Salix Wizard
Posts: 6238
Joined: 6. Jun 2009, 17:40

Re: Awry text after monitor upgrade

Post by gapan »

That's a weird bug. The difference is probably in the kernel. I'd like to see you try to move to a newer kernel in Salix, but since it works for you with a DP-DP cable, I guess we can leave it at that.
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DrCR
Posts: 58
Joined: 30. May 2014, 05:14

Re: Awry text after monitor upgrade

Post by DrCR »

Good point. I don't mind a trying a kernel upgrade, but since that's a realm I've never bothered with, I'd need some hand holding / an idiots guide.

I can try Slackel 7.3 if that might be a quick way of trying a newer kernel with a sibling distro.

Without going into detail, I'm exploring the non-DP-DP routes for this monitor, and accordingly I don't mind putting a bit more time into sussing out what's up with the DVI-HDMI route. (In a nutshell, with DP-DP the screen doesn't wake / holds back computer boot most of the times I attempt to boot. Kepler video card, fyi.) If the HDMI-HDMI route doesn't prove satisfactory, I'll likely be sending this monitor back since, despite how great the panel is, this monitor would be too expensive to settle with DVI's limit of 60Hz. Maybe I'll need to wait for someone else's package e.g. LG to do this panel justice.
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gapan
Salix Wizard
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Joined: 6. Jun 2009, 17:40

Re: Awry text after monitor upgrade

Post by gapan »

Yes, Slackel 7.3 would certainly do.

For upgrading the kernel in Salix you could try these instructions: https://docs.salixos.org/wiki/How_to_in ... ent_kernel
Go for downloading the newer kernel packages from slackware current and upgrading them manually.

According to my experience though, HDMI-HDMI should work with no issues whatsoever.
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DrCR
Posts: 58
Joined: 30. May 2014, 05:14

Re: Awry text after monitor upgrade

Post by DrCR »

Slackel loads to 640x480, which the monitor perhaps understandably appears to be interpolating rather poorly. But other than that, Slackel looks good.
https://postimg.cc/qzM8vSt3
https://postimg.cc/vgsnFNFD

Thanks for the link and insight. I'll plan to do a kernel upgrade in Salix some time this week and will update with the results. Before then, I'll check how my present Salix fares with HDMI-HDMI.
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