2 monitors, different resolutions

[knobby]

Hi folks,

I'm running Mint 19 with 2 Lenovo monitors which are exactly the same. One is connected to the VGA port of a Radeon HD5450 graphics card, and one is connected to the DVI port of the same graphics card using a VGA to DVI adaptor. The problem is that only one monitor is recognised and allowed to run at 1440 x 900 resolutions, while the other monitor is not recognised as as such is only allowed to run at a maximum of 1024 x 768.
Is there any way to force the unrecognised monitor to run at the higher resolution?

(PS... I was using a Nvidia GT210 graphics card but this was the same)

[lsemmens]

VGA to DVI adaptor

I'm wondering if this is your problem. Is there facility to connect the monitor directly i.e. VGA-VGA or DVI - DVI?

[knobby]

Unfortunately not. But it is the one connected directly to VGA which is not recognised - the one with the DVI adapter is the one which is recognised.

[catweazel]

(PS... I was using a Nvidia GT210 graphics card but this was the same)

This is a limitation of VGA. It can't do 1440 x 900, which is WXGA(II). The problem will be your very old video card and the connections it provides. Given the age of that card is close to 11 or so years, it's probably time to upgrade. You can't expect old equipment to run the latest and greatest OS.

[BG405]

There are a few variants of this card, with a few different brands, it seems. Could you let us know exactly which one you have?

Only resolution specs I've found so far (which might not be the same as your card) are as follows:

Code: Select all

Max Resolution Details
DVI: 2560 x 1600 / VGA: 2048 x 1536

Could you please post the output of Terminal command xrandr, in between [code] and [/code] tags? Easiest to use the [</>] button at the top of the reply window.

It's also worth trying another cable if you have one & haven't already done so.

Is there any way to force the unrecognised monitor to run at the higher resolution?

Yes, that should be possible.

[rene]

It's also worth trying another cable if you have one & haven't already done so.

Emphasizing the above: it's probably the only thing worth trying. Your symptom matches a not-fully wired VGA cable disallowing EDID transportation from the monitor; the computer not getting monitor information and hence limiting itself to standard (S)VGA resolutions such as the 1024x768 you get. The issue is quite unlikely to be other than cable...

[BG405]

Your symptom matches a not-fully wired VGA cable disallowing EDID transportation from the monitor

It indeed does. Or a dodgy connection (have experienced colour dropout on one or more channel(s) due to this; required some plug wiggling & re-inserting to fix it), if the same cable worked previously.

[knobby]

Hi Folks,

I've just tried a new cable but that didn't make any difference.
The graphics card is a Sapphire Radeon HD5450 card with 1Gb DDR3

Just ran the xrandr command and got this:

Code: Select all

Screen 0: minimum 320 x 200, current 2464 x 900, maximum 8192 x 8192
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 connected 1440x900+1024+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900      59.89*+  74.98  
   1280x1024     75.02    70.00    60.02  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    59.94  
   720x400       70.08  
VGA-0 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768      60.00* 
   800x600       60.32    56.25  
   848x480       60.00  
   640x480       59.94  

[knobby]

I took the cable from the non-recognised monitor and plugged it into the DVI adaptor. I then took the cable from the previously recognised monitor and attached it to the VGA connector. Both monitors are now recognised and running at 1440 x 900.

No idea why this has worked but it has!

[BG405]

It's great that they are now both working. It would be useful to see the xrandr output again in this state, to see if all the available resolutions are listed for both monitors & any differences; it'll also help provide a solution if the "fix" doesn't survive a reboot.

[knobby]

it'll also help provide a solution if the "fix" doesn't survive a reboot.

How did you know this????
Yep, restarted the computer today and I'm back to the same issue, although the monitor now running at 1024 x 768 is the one connected to the DVI port via the adaptor. The one connected directly to the VGA port is at 1440 x 900.

[knobby]

Swapped the monitor connections around again and I'm back to 1440 x 900 on each monitor. Here's the xrandr output:

Code: Select all

Screen 0: minimum 320 x 200, current 2880 x 900, maximum 8192 x 8192
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 connected 1440x900+1440+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900      59.89*+  74.98  
   1280x1024     75.02    70.00    60.02  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    59.94  
   720x400       70.08  
VGA-0 connected primary 1440x900+0+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900      59.89*+  74.98  
   1280x1024     75.02    70.00    60.02  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    59.94  
   720x400       70.08  

[BG405]

How did you know this?

A hunch. I think the machine is getting the EDID from the other monitor when you swap them.

Could you confirm whether it's always the same monitor with the issue, whichever port it's connected to, and which one? I know it's a pain doing the reboots for this, but that way I can write something you can put in as a startup item, to set the resolution.

[knobby]

Could you confirm whether it's always the same monitor with the issue, whichever port it's connected to, and which one?

Yes it is the same monitor. This is the primary monitor and is connected to the VGA port.

[knobby]

but that way I can write something you can put in as a startup item, to set the resolution.

Any joy with this? It's driving me nuts!!

[BG405]

Hi sorry I got waylaid. Could you try these commands in Terminal when the monitor resolution is unavailable:

Code: Select all

xrandr --addmode VGA-0 "1440x900"
xrandr --output VGA-0 --mode "1440x900"

If the first command produces an error, let us know. Might need to add a mode to use.

This will not survive a reboot. If it works, the necessary commands can be added to a startup command or script.

NB: If it's the other monitor, substitute VGA-0 with DVI-0 accordingly. The display(s) will flicker briefly; this is normal.

[knobby]

First command didn't give an error.
Second command worked and changed the resolution to 1440 x 900 .......... but............

One screen image overlaps the other by around a third of the screen area. For example I'm looking at this page on the DVI monitor and have my browser maximised. On the VGA monitor I can also see from the left hand side of my browser across to the "font colour" icon.
If I go to Preferences>Display it shows the two monitors but one is actually overlapping the other. If I move the monitor icons around I can get them to be side by side, and when I press "Apply" the monitors correct themselves.

[BG405]

If I move the monitor icons around I can get them to be side by side, and when I press "Apply" the monitors correct themselves.

Do you mean by "correct" that they revert to overlapping? I've had to fight with the monitor positioning in Cinnamon in the past; they seem to have a mind of their own & keep springing back.

Could you confirm which monitor is primary (DVI or VGA) and which way round you have them? It should be possible to set the display position accordingly. Confess I'll have to do a bit more research for this.

[knobby]

No.... correct as in the images are no longer overlapping.

The primary monitor is the VGA one; the DVI one is to the right of the VGA one as I sit and look at them.

[knobby]

I solved this issue using this tutorial on Youtube:

https://www.youtube.com/watch?v=-ABHN8BtWh8