External monitor resolution changes after updates

Support Graphics & Display
1

Hi all,

I have a weird issue, and I can’t seem to find anything about it online (either because nobody else has encountered it, or I’m not using the right search terms :thinking:)

I use a Lenovo Carbon X1 laptop, hooked up to two 27" external monitors in “extended” mode:

  1. A ViewSonic through a USB-C port to a DisplayPort on the monitor
  2. An Asus through the HDMI port to an HDMI port on the monitor

Both these monitors run at their max possible 2560x1440 resolution in the normal course of operation.

But when I run a pamac update, towards the end of the update process, the second monitor (Asus) changes resolution to 2048x1152, and the Display Config utility shows me that it’s the max possible resolution for the monitor.

I then have to unplug the HDMI cable from my laptop and plug it back in, after which I can change the resolution back to 2560x1440 on this monitor.

I think it roughly happens around this step of the update process:

Creating system user accounts...                                                                                                                                            [1/15]
Registering binary formats...                                                                                                                                               [2/15]
Reloading system manager configuration...                                                                                                                                   [3/15]
Reloading user manager configuration...                                                                                                                                     [4/15]
**Reloading device manager configuration...                                                                                                                                   [5/15]**
**Arming ConditionNeedsUpdate...                                                                                                                                              [6/15]**
**Refreshing PackageKit...                                                                                                                [7/15]**
**Reloading system bus configuration...                                                                                                   [8/15]**
Copy Firefox Distribution Settings                                                                                                      [9/15]
**Updating fontconfig cache...                                                                                                           [10/15]**
**Updating 32-bit fontconfig cache...                                                                                                    [11/15]**
Registering Haskell modules...                                                                                                         [12/15]
**Updating icon theme caches...                                                                                                          [13/15]**
**Updating the info directory file...                                                                                                    [14/15]**
**Updating the desktop file MIME type cache...                                                                                           [15/15]**

(suspected steps enclosed in asterisks above)

Does anyone know what might be causing, or how I can debug further? is there some log that I can tail while this is happening to pinpoint exactly when this happens, so that I can investigate further?

Thanks in advance :pray: