I need to disable kms drivers so resolution and other settings work better for a full screen text application. I use i915.modeset=0 as a boot command to do this. When this is set the monitor doesn’t seem to detect display on wake up from rtcwake -m mem ... or systemctl suspend. Swap size below 4GB isn’t an issue because monitor detects display on wake up when i915.modeset=1 is set as well as swap space being bigger than memory. I have tried changing source on the monitor and power cycling it, but it still doesn’t detect output. Appending no_console_suspend boot command doesn’t work. Replacing no_console_suspend with i915.enable_dc=0 doesn’t work. Grub was updated with /sbin/grub-mkconfig -o /boot/grub/grub.cfg each time. The primary video controller output in the bios was auto and I changed it to onboard and I still experience this issue. This is experienced with Debian 11 with an Intel iGPU. What do I need to do to get the monitor to detect output from the iGPU after wake up from S3 with i915.modeset=0 on boot command line?

Disabling KMS, whether by using nomodeset or i915.modeset=0, cripples the graphics system. Disabling KMS is primarily designed for enabling troubleshooting on a system on which no functional video output occurs. Find a way to accommodate the application to a some kind of KMS-enabled environment, or suffer the consequences.

Text can be configured for fullscreen aka vtty session for various needs. So too can resolution be changed. e.g., if the display's native mode is 2560x1440, but 2048x1024 would be more useful, and the display supports it, append the following to the linu line in grub:This only works if KMS remains enabled.

I was able to resolve this with reassurance from https://www.kernel.org/doc/Documenta...ower/video.txt. It requires vbetool is installed. I needed to do when the the monitor is active and working and then I could do (FYI: following command spits out Function not supported despite the command working) after computer wakes up. At this point the display has artifacts and all I have to do is refresh the display without kernel text showing up is killing and restarting the display process. Changing vt with function keys or chvt to a different vt and then back to desired one sort of works, but kernel text shows up and brings the full screen text display out of view and necessitates the display being refreshed for my purposes. I'm not sure if the savestate dump actually has contents of the video buffer which may have sensitive info so if someone wants this to be repeatable I would err on the side of caution and make new savestate before sleep and then delete after wakeup.