tl;dr: Enable DRM for all graphics output and retire fbdev drivers in TW.

Hi!

For quit a few releases, Linux' DRM stack has been able to provide display output from the early boot stages on. Next year, we want to modernize Tumbleweed's graphics stack and use DRM for all graphics output.

To get graphics output during the early stages of booting, Linux
still uses fbdev infrastructure and a few HW-independed drivers, such as efifb and vesafb.

This functionality is now available in DRM as well. We will switch early-boot graphics from fbdev to DRM and retire the related fbdev drivers. Fbdev userspace interfaces (i.e., /dev/fb0) will still be available via the new driver.

The change has no effect on graphics output of the fully booted machine. Just as now, at some point during boot, a hardware-specific driver, such as amdgpu, i915, etc., will take over the display.

Why switch? The generic DRM driver provides a fallback for all systems without hardware-specific drivers. Even with broken hardware drivers, generic DRM can most likely boot and provide graphics output. This isn't easily possible with fbdev. Fbdev has been out of date for several years. Modern graphics userspace slowly uses the ability to run on top of fbdev. Most notably, wayland compositors are affected by this. We also have received reports about systems being unable to boot because of fbdev.

TW's X11 and userspace should be ready (sans bugs). If you want to test, Takashi provides a kernel that has full-DRM enabled at

  https://download.opensuse.org/repositories/home:/tiwai:/simpledrm/

If you install and boot the kernel, you should ideally see no difference. Once booted the hardware's driver will do the graphics output. To test if you booted with generic DRM, do

  dmesg | grep drm

Here, this gives

drm...
[    7.933792] [drm] [nvidia-drm] [GPU ID 0x00004100] Loading driver
[    8.967538] [drm] Initialized nvidia-drm 0.0.0 20160202 for 0000:41:00.0 on minor 0
[269005.669940] [drm:drm_new_set_master [drm]] *ERROR* [nvidia-drm] [GPU ID 0x00004100] Failed to grab modeset ownership

on

Linux linux-mkay 5.15.7-1-default #1 SMP Wed Dec 8 08:54:39 UTC 2021 (b92986a) x86_64 x86_64 x86_64 GNU/Linux

Despite the error mentioned in the last line I encounter no problems with my graphics setup. But I don't have the expertise to know what it means.

regards, Jogchum

on the command line. The output should mention 'simpledrm' somewhere. If you want to run your system with the generic driver only, pass

  nomodeset

on the kernel command line in Grub. The booted system should run with only software rendering, but provide useful output via X11, wayland and console.

We welcome bug reports. If you find issues, please leave a comment in boo#1193250

  https://bugzilla.opensuse.org/show_bug.cgi?id=1193250

Best regards
Thomas